Diesel engine swaps

I know this subject has been brought up before but it usually centered around the Cummins 6BT which in my mind is a giant heavy truck engine that doesn't belong in a car (and the 4BT just isn't ballsy enough). I have a few local car buddies who own old-school Mercedes diesels and those things are pretty neat but a tad too small; I have an idea to diesel swap a C-body so I can go on road trips and drive it when I feel like it but not get eaten alive by big-block gas mileage. Anybody familiar with other automotive diesel engines which might be good swap candidates?