Ya the crossfires are a but fat. I heard that you can trade the older regs in for a discount one of their new ones though, which is shorter. You'd have to call and ask them about that.
I don't know who makes a double dovetail anymore. You'd have to check around I guess. I's easier just to use a shorter or thinner reg.
Etek 3LT grey/black f/s
Valken Proton greyish/black f/s
68 4500 PE stubby, LP output f/s
68 4500 AIR tank(no reg) f/s
Creed/demon eyes f/s