I think I got the donor car match. To the knowledgeable masters on all things Mercedes, here's my thought.

Donor car: 1995ish c220

I'm not sure on engine dimensions just yet, but the wheelbase and track is almost perfect! It makes me think that I could take the body of the w110 and put it on the newer frame. The only downside would be going from a manual to an auto.

c220: wheelbase (inches): 105.9, front track (inches): 58.8, rear track (inches): 57.6

w110: wheelbase (inches): 106.3, front track (inches): 58.3, rear track (inches): 58.5

Thoughts from the peanut gallery?