INETD......You said:
"The $800 rear strut has got to go. I'm on a pilgrimage to find a better solution."
My question to you is, are you sure you genuinely need them? They are pretty darn bulletproof from what I know/have been told. If the problem is thumping noise it is't the strut that is causing the problem. The upper bushing is replaceable (what causes the thump noise) and it is the accumulators that caused the problem originally, much cheaper at $90 or so each. Even if you do in fact need them they can be had at discount for about $400...check out the host here!
I love your enthusiasm about the 500 W140....we need more like you