Now that I got a drive shaft from another source, Ensign finally came out the woodwork and came up with the original one. Perfect timing. It is, in fact, identical in size (42 inches) to the alternative shaft that came out of the 250SE.
I tried to get the front and rear shaft counterbalanced locally, but apparently, I was told they could not do it. I have several ways I can connect the front and rear to find its original setup. It will be a alot trail and error. Hopefully I won't experience a shimmy.
I will have to make threaded slide plates for the center bearing as the originals are lost in space and it seems apparent that MB does not provide a listing for them.
The saga of Project W111 continues......