Several years back I owned a S&W 617 8.375" revolver on which I mounted a Burris 2.5x pistol scope. Don't remember the model # but was very pleased with it. But actually I prefer 1x red dots on handguns unless I'm able to rest the handgun. I found holding this BIG HEAVY revolver still enough to maintain a good sight picture with a 2.5x difficult.
Kel-Tec's prototype RMR-30 30 round .22WMR carbine, based on the PMR-30 is rumored to be released in 2011. This could not only be a fun gun but a serious one as well.