Illbike cancer is legit. Dartmoor has some, but 22.2 stems are usually longer than what u want. I say go with a good 25.4 stem and get bar shims to convert ur clamp area from 22.2 to 25.4 thats what im using. NS quantum with shims and an NS district bar which is 22.2
I personally like 50mm reach stems (which is very common in bmx) so it's easy.
If you are wanting shorter reach stems, flatland bmx tends to have those: http://flatlandfuel.com/stems.aspx 25mm, 36mm, 40mm etc etc. I think the Colony, Madera, and S&M would be my favorite out of the ones at flatlandfuel.