I bought a Jak Pak, which is supposed to be used as for portability of pneumatic tools. It fits paint ball tanks and has a regulator. I have never actually used it, since I can't get paint ball tanks filled in the city.
I have all my lines set up with quick disconnects, so my plan is to do the same with the Jak Pak so that I can change out whatever fitting I need on the line.
I think it was like $40 on ebay, which is a deal compared to the Leland regulators you can get at some on-line homebrew places.