I believe that 10mm is experiencing a resurgence of sorts. It is small and slow but that's OK - when dealing with 10mm, any sign of progress is considered good. I can recall four things that seem to support this in the last 12-18 mos. (in no particular order):
1.) Dan Wesson, already producing two models in the caliber, re-introduced the Razorback/RZ-10. This is after CZ had acquired them. I can't imagine a company like CZ approving RZ production if they did not feel it would be a money maker. Makes you hope that CZ will start producing their own 10mm pistols.
2.) Bob Serva, formerly of DW, launched his own company and plans on producing some models in 10mm. He is clearly a 10mm devotee as evidenced by his time with DW. Have heard unsubstantiated rumors that Fusion will be making a Longslide in 10mm (think DW Global Hunter) -
Along these same lines, have heard DW will be adding to the model line next year as well.
3.) Wilson Combat has made 10mm an option for the CQB model. Interesting that a semi-custom firm like that would choose this caliber.
4.) Fiocchi has started making a 10mm load
- 200 grain FMJ at ~ 1050 FPS. It's so new that it hasn't even hit the market yet. That's fairly pedestrian performance but, to me, Fiocchi is the last company that I'd expect to begin offering 10mm. Maybe there's an Italian connection with Tanfoglio?
As other posters have noted, 10mm will remain a fringe caliber. It will never enter the mainstream - unless someone like Colt, S&W, or SIG takes a chance and begins offering guns in it again. Don't see that happening so us 10mm fans will keep being a very vocal minority.