Pony up and buy an E320CDI/Bluetech :-).
You like the W126's, so maybe, the perfect Mercedes would be a 300SDL? it SHOULD only be a 1-2K difference. Right now, there's one on the local Craigslist for $5250, no idea how nice it is.
http://portland.craigslist.org/clc/car/327199391.html Kevin in Hillsboro, OR1983 300SD 267Kmi, Ursula