Are you set on an integral suppressor over a removable one? Often integral suppressors either can't be dissasembled or are simply a pain to do so. You're going to want to disassemble it; there's a lot of lead and carbon fouling that stays in a .22 can and is very hard (or even impossible) to completely remove without disassembly. Also, integrally suppressed .22s often have ported barrels that shorten the overall length of the pistol, but give you an effective barrel length of only a few inches whch will reduce velocity compared to a standard .22 barrel.
I'd go with a top-of-the-line serviceable .22 can like the Spectre II and use a threaded-barrel Mark III as a host. It will still be ridiculously quiet, you'll have a little more velocity due to a longer effective barrel length (but the barrel will still be short enough that most regular .22 ammo will be subsonic), the can will be completely serviceable, and you can take it off and use it to suppress anything up to a 5.7mm.
0331: "Accuracy by volume."