anyone know who manufactures rifles in 30 carbine?

Go to www.fulton-armory.com/M1Carbine.htm

I think Ruger made a Bearcat revolver that was chambered for 30 carbine. seems like someone like TC or NEF/H&R made barrels for it as well. I think they are all kind of hard to find though.

Auto Ordinance makes brand new M1 Carbines, although they are not exact copies of the GI design, they have a perforated metal upper handguard instead of wood......there are a couple of others that have been marketed that you do not want, I think Universal is one, can't recall the other off-hand.