lpb,
It may be possible to decrease the thickness of the bushings in the fronts of the control arms and shim the backs. When I had the engine and trans out of my '74, I was able to move the whole drivetrain back a bit by placing all of the shims in the ZF mounts in front of the bushings. The control arms actaully pivot at the bushing, whereas the ZF doesn't move, so maybe if you shot Goram Malmberg an e-mail, he'd help shed some light on if will work or not.
Michael