Tim, the more you respond the more the picture comes into view. Have you thought of quarter elliptic springs? One, they're very cost effective, particularly as compared to coilovers. Two, they act as two of the four links for locating the axle. You'll still need two bars mounted to the top of the axle housing, and a panhard bar to control lateral movement, but you'll have a relatively simple and, comparitively inexpensive setup. And plenty of room to route exhaust if you're going underneath.

BTW, heed Richard's word about the rear axle straightening after ANY welding on the housing. I bought a '39 Chev coupe with an 8" Ford housing that had had several brackets welded on. Shortly after I got it it munched an axle bearing, causing me to get a flatbed haul home. I pulled the housing, took it to my buddy who has the tooling for straightening, and that housing had about a 3/8" "bow" in it. Doesn't sound like much, but it's enough to hurt the bearings.