Gun Parts Corp still list a .22LR blued cylinder.
Note that these may not be genuine factory cylinders, since Gun Parts sold a lot of replica cylinder in years past:
http://www.gunpartscorp.com/catalog/...spx?catid=6639
Coltparts also list blued .22LR cylinders but you'll have to call to get availability. Their site has problems linking to the cylinders.
http://www.coltparts.com/index.html
Also, note the above info that these cylinders often don't just drop in. They may require some fitting and adjusting by a competent cylinder man.
Among other things to be checked/fitted are head space, barrel/cylinder gap. cylinder end shake, chamber/bore alignment, and timing.