This is probably real dumb suggestion, but what about fitting sway-aways, slacking them off so the front end is real low, then just fitting coilovers to bring it back up. What would the effects of the two springing systems working against each other be? If you had shocks with seperate re-bound and compression settings, you could wind the re-bound damping up a bit. The original torsion springs are a proven method of locating the trailing arms.
Another probably dumb thought is replacing the block in the middle of the beam with some kind of bearing (a weld in unit like sway-a-ways) that locates the springs in the middle but lets them rotate freely. This way the torsion leaves would act as an anti roll bar but leave the springing up to the coilovers.
Pls don't laugh at my suggestions, I'm no engineer - thats why I'm running it all past you guys before I try anything
