I have the w56 forward shift tranny/t-case with both shifters in one base plate. I looked around for any manufactured ones, and could not find anything for my application, so I made my own, and did a write-up on it.
http://www.fattshack.com/phpbb3/viewtopic.php?f=4&t=1270
It was my first attempt to do something like this, but turned out really good, and I love the tighter feel of the shifting motions. I used a 1.5" spacer, and extended the shifters (both) the same amount. It will raise the shifter up the same amount, and since I am running a BL, I do not know whether or not there would be clearance issues without one.
Thanks for posting! That is a good and valuable thread. Sounds like 1.5" is the way to go. And yet one more reason I like body lifts. I have a 2" so we should be good there.