I am interested in the RIA TCM. It comes with a 9mm barrel but also has a .22 caliber barrel necked down from 9mm. I could see ammo for the .22 being hard to find but it would be pretty simple to make if you reload.
I would imagine it would be a pretty awesome range toy and fair substitute for a medium range weapon (PDW).
Not a lot of experieance with the RIA gun's but they seem pretty popular and get good reviews as a low cost 1911 option.