I have a .40 barrel for my 10mm full size witness. Does that count?
I too am fond of the ergonomics of the CZ and witness. If the grip on the full size 10mm is not too big for your hands, I would reccomend it. There's a lot to be said for this combination. Load up the 10mm for a woods gun, or serious social encounters. Drop in the .40 barrel for inexpensive plinking. Or if you prefer, pickup a .357 Sig barrel and add a third cartridge into the mix! If you buy a witness, I would reccomend you also purchase a Wolff "Calibration" spring kit for it. The witness pistols appear to be undersprung and need the + power recoil springs to decrease the slide velocity. I have found the 16# spring works well with my .40 handloads, and the 20# with the 10mm full power loads. Mine took a bit of tinkering to make it reliable, but was well worth the trouble.
Savage