I have been shooting one of the Rock Island convertible 22TCM pistols for more than a decade now
Mine is the Ultra Target model and obviously it is pre-rail (I hate rails on 1911s)
The Ultras are double stack pistols. Mine holds 17 rounds of 22TCM, 9MM or 38 Super depending on which barrel I have installed. Yes you can shoot 38 Super in the same pistol if you add a 3rd barrel. I have never shot one of the single stack variants.
BTW you do not need to shoot the 22TCM9r in a 1911, the slightly shorter projectile loaded into the 9r ammunition is necessary in the Glocks
22TCM is an awesome cartridge. At over 2,000 FPS from a 5" 1911 it is a Very flat shooting round.
The 22TCM is Very accurate, at least in my pistol, and it Barks more like a 357 Magnum
There is very little recoil from the 22TCM