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:
Coltparts also list blued .22LR cylinders but you'll have to call to get availability. Their site has problems linking to the cylinders.
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.