Dom,
I actually designed our
outboard-braked rear with an upper link at first, but also made it so it the plunge distance of the half-shaft would be at a minimum. I did it so well
that the upper arm is essentially redundant if the length of the half-shaft is constant. In the end, I chose to keep everything simpler (and cheaper) by not using an upper radius arm. Because I bolt on the upper link attachment, my hub carrier is still amenable to a radius arm, but our subframe doesn't have provisions, and would require a curved arm to fit. More weight...
RDorman,
The Corvettes used the same system as the Jag - the half-shaft doubled as the upper link - from '63 to the C5.
We make our half-shafts by taking the original pieces and turning down the ends to fit inside a heavy piece of tube. They are a press fit for about 3", then they are welded. If the weld breaks, the axle may spin, but it tends to stay together. The suspension won't "fall over" - you just lose the ability to transmit torque. All of that is quite academic though. Since we went to a heavier tube (quite a long time ago), we've never had a problem - even with guys using slicks for dragging.