if your thinking JeepSpeed'ish, then check out the JeepSpeed area of this site... lots of great information there.
If your going JeepSpeed, there's no reason for the rear coil conv., as its not allowed.
RK, TNT(Treks), Claytons all do rear coil conversions I believe.
As for Rusty's, he'll stay in business because his prices are low, a lot of people DO like his stuff (for whatever reason) and not everything he sells is crap (he distributes a lot of other peoples stuff IE engine/performance parts) You could get lucky and get great service, or the opposite, your guess is as good as the next guys.
You don't seem to know exactly what you want to do, I'd figure that out, before you stat thinking about stepping into rear coil conversions. You can do a lot on 33's short arms and rear leafs...