There are quite a few kits out there to convert your 1911 to shoot the cheap and plentiful .22lr round. Kimber, Marvel Precision, Ciener and Advantage Arms are usually the brands brought up when people ask about 1911 .22lr kits.
There are also quite few 1911 .22lr pistols that have hit the market recently, most notably from GSG, Sig Sauer, Browning, Colt and Chiappa (Sig’s .22lr 1911 is actually made by GSG). The GSG 1911 probably being the most popular of the bunch, I actually own one and have put thousands of rounds through the pipe over the year and a half I’ve owned it. Well it looks like GSG has also released a .22lr 1911 conversion kit, and at a pretty darn good price. It’s listed at $199 over at Americantactical.us and comes with the slide, barrel and one ten round magazine.