A couple of years ago, the record-breaking auction of a collection of previously-unknown Patek Philippe watches with titanium cases confirmed a couple of truths: that a Patek in a non-precious metal can be far more valuable than its gold or platinum equivalent; and that, for the right client, anything really is possible.

We knew of a handful of one-off titanium watches Patek Philippe created for charity auctions; but the idea of a secret suite of five, including a Sky Moon Tourbillon and an ultra-thin Calatrava with a huge, flat diamond set into the case-back instead of sapphire crystal (see left), was frankly beyond imagination.

Whoever the seller was, only a collector of pre-eminent importance to Patek Philippe will have had the sway to commission something so remarkable.

That person remains anonymous. The auction did, however, give us a peek into the top-secret world of bespoke watchmaking, one that is quietly thriving in today’s market where exclusivity has become one more marketable commodity.

What you can get is dependent only on the depths of your pockets, the length you’re prepared to wait and sometimes – with Patek Philippe, at least – your relationship with the brand’s elders.

The tradition of unique watches made to the whims of powerful clients is long- established in the watch world, of course, the most famous examples being Patek’s Supercomplication for Henry Graves Jr or Abraham Louis Breguet’s creation for Marie Antoinette.

Last year’s reference 57260 mega-complication from Vacheron Constantin, the modern inheritor of those watches’ legacy, was itself a private commission. And indeed, the options for the modern collector are broader than ever, ranging at Vacheron Constantin alone from a bespoke dial up to, well, the most complicated watch ever made.

In many cases, the métiers d’art watches that brands wheel out at SIHH and Baselworld are no more than shop windows for what’s possible under private commission.

Think of Jaeger-LeCoultre’s recently launched “Hybris Artistica” collection, the heavy emphasis on enamel and artistic dials from brands like Vacheron Constantin, Piaget, Laurent Ferrier and Jaquet Droz, or indeed the avalanche of unique piece artistry Cartier unleashes each year at SIHH.

Each of these can be seen simply as offering inspiration for collectors who want things made to their personal specification.

At Cartier, in fact, over a thousand commissions are taken on each year, ranging from decorated cases to extravagant stone settings and – the most common request – the reproduction of pets on a dial.

At Vacheron Constantin, access to its Ateliers Cabinotiers bespoke service – the platform that delivered the 57260 – is open to anyone by appointment via its Bond Street boutique. Upon speaking to the store director, notes are taken and information relayed to the Ateliers Cabinotiers department in Geneva. Depending on the complexity of the request, the client may be invited to Geneva to meet with the Ateliers team, while an “ethical committee” vets each request. Waiting times range from 12 months to eight years for the 57260.

One watch designed from the outset to be customisable is the Jaeger-LeCoultre Reverso, whose legend was established on the possibilities it offered for engravings and paintings on its flippable case-back.

An online portal (personalization.jaeger-lecoultre.com) today offers basic embellishment options along with a platform for more sophisticated requests – a studio at its Le Sentier manufacture is entirely dedicated to creating specially enamelled Reverso casebacks, for instance.

Jaeger-LeCoultre is also widening the possibilities with a new service offered at its flagship boutiques, launching this April in London. “Atelier Reverso” extends customisation to its Duo and Duetto Reversos (dual timezone models with a dial on either side, and therefore no caseback for decorating), with a range of dial possibilities for the GMT side, including mother of pearl marquetry, diamond settings, and various colour options, along with different choices of interchangeable straps (itself a growing trend in watches).

For many collectors, though, the hunt for something really unusual will lead them away from the established brands, and one needn’t necessarily look as far as Switzerland. Roger Smith’s bespoke Isle of Man practice is well known, for those prepared to accept a years-long waiting list and six-figure prices; but newer, more affordable options are emerging.

Struthers London, the husband-and-wife team behind a set of historically literate watches made in association with the boutique carmaker Morgan, offers bespoke watches based on historic movements that it sources and restores specially.

One sensational example is a diamond-set women’s watch made to house the stones from the client’s vintage Tiffany earrings, shown below. Case, dial, hands and setting were all made from scratch, drawing partly on skills available in the Birmingham Jewellery Quarter where Struthers is based.

Inside the watch is an IWC movement from the 1940s – not exactly the caliber one might expect, but one whose curving bridges take on an even more elegant aspect having been newly engraved and embellished.

“One of the most important things for customers is coming into the studio, chatting about watches and seeing it come together,” says watchmaker Craig Struthers, who has capacity for around 10 bespoke watches per year, with prices starting at around £30,000. A new “tailor made” option is customising an existing Struthers design, an octagonal ladies’ watch called the Kelso, a service that starts at £16,500; a men’s model is in the works.

Norwich-based start-up Garrick has also found a huge appetite for customised watches – to the extent that co-founder Dave Brailsford reports that in the past year, the company hasn’t produced what he’d call a “standard” model. Its original watch, the Shaftesbury, was designed with customisation in mind, featuring a modular dial with an array of choices for dial colours, hands and chapter rings, and the option of a finely-finished Unitas movement featuring watchmaker Simon Michelmayr’s in-house free-sprung balance. Demand for the latter has been particularly overwhelming.

Like Struthers, Garrick keeps its clients heavily involved in the creative process, with an online platform hosting a constant flow of from-the-workbench photographs where customers can follow the creation of their special watch.

“For proper collectors, there’s so many watches and brands out there, they do want something unique,” says Brailsford. “I thought originally that we might make one or two bespoke watches every couple of months, but we’re overrun with requests.”

If you offer it, so it seems, they will come. Particularly if, like Garrick, the cost is relatively affordable, sitting currently in the low thousands – though the offering will increase in value as Garrick begins working with an exclusive movement (incorporating Michelmayr’s balance) being made for it by UhrTeil, the industrial unit of bespoke Swiss watchmaker Andreas Strehler.

Brailsford reports a constant stream of requests and concepts from excited potential clients, often accompanied by detailed drawings – though comprehension of what is possible in a watch, and particularly how a movement dictates size, can be understandably lacking. For complex requests and high complications, though, one does have to turn to Switzerland, where the aforementioned Strehler is arguably leading the charge.

Strehler, 44, is nothing short of a horological dynamo, having invented a slew of complex movements in the past four years – including a moon phase accurate to a day’s deviation every two million years. Those are in production watches announced publicly, but even these generally end up in variously customised forms when delivered to collectors.

But Strehler also creates watches completely from scratch. To the official new movements you could add three that ended up being developed in a single project for a complex bespoke world timer.

Moreover, every time Strehler creates a part for a watch he creates several duplicates, all to the same exact tolerances, to ensure that the watch can be serviced in years to come. Strehler pays a finder’s fee to those who put him in touch with clients once a watch is made, with prices starting from CHF 57,000 for his entry-level Time Shadow (unveiled during SalonQP last year) up to half a million for a Grand Complication he’s currently working on. A fortune of course – but less than half what you’d pay for a titanium Sky Moon Tourbillon at auction, should one ever appear again.