They may be cool, but they are next to useless. They're just another thing to break. Why do you want a scope on a snubnose? There is no common sense to that, they're not accurate enough, and a snubnose was ment for conceiled carry. It's just not something that needs optics. Once again, they're cool but pretty useless overall. There are conversion kits for 1911's, some broomhandle Mausers and Browning Hi-Powers accept shoulder stocks, the TC Contender can be converted... The problem is that if you put on the buttstock without the longer barrel, you're an instant felon (illegal short barreled rifle, except for some broomhandle mausers which are specifically exempted.) There are a few legal transferable class 3 AK47's out there. Expect to pay about $10-$15k for an original Russian (AK47) or Chinese (Type 56,) plus paperwork, fingerprints, police signatures, a full background check, a $200 transfer tax, and up to a year of waiting. That's if you live in a state that'll let you, and you're over 21.

That aside, there are civilian legal semi-auto only versions. I have two, a Mk.II (Romanian AK-74 clone) and a Saiga .223 (Russian AK-101 clone.) This also assumes they aren't banned in your state.