I was looking at these awhile back, along with other pistols that fire variants of the .22 cartridge. I think it all comes down to the cartridge being made for a rifle and not a handgun. There is not a huge selection of them out there. If I remember right, Taurus and Ruger had a few to pick from. I don't think they were all that popular and may have not been brought forward into this year's catalog.
If you can find one or someone can order one for you, expect to pay $350-$500 for a Taurus (depending on model) and about $100 more for a Ruger.
~rc~