I asked a few years ago and went with a custom built one.
They will sell you a frame and fitted slide (40S&W) then you can build it yourself or send it to one of the other shops.
The time was mostly waiting for Bar-sto to fit the 10mm barrel.
It is really nice, after all the time taken to gather parts and have them fitted.
Good luck on your build/Search.
One note, he did build a few 10mm guns, on the premier type, back in the early/mid 90's. you may have to search for one.
The 10mm is, if anything, a fringe cartridge. It's popularity has seen its zenith and there are only a realtive few remaining devote's. This is not said to disparage the cartridge, just to put it into perspective from a manufacturing point of veiw.
The issue is in the bbl. Baer buys blank bbls from Freddy Kart and machines them to his specifications. He uses a proprietary rifling (landing) design, upon which his reputation for legendary accuracy has largely been forged. So, to re-tool for a fringe caliber, when you are selling every single pistol you can produce, in the calibers in which you already produce them, and are tooled-up to produce... just makes no sense.
Add the fact that Dan Wesson makes a decent, mid-range 10mm and that Fusion is making a really nice custom 10mm... the margins become even narrower.
Kimber made a limited run of their Stainless Target II in 10mm. I have stumbled on two of them. This one had been back to Kimber for 30 LPI front strap checkering and fancy grip panels. It was used but unfired.