I would consider the sprinter engine or the Liberty engine. Somebody probably makes a mid size 4 cylinder diesel like Kabota with a turbo or an older Deere industrial or Yanmar.

 

Do you want me to finish the old saying??

 

Working on a 4cyl Cummins in a Jeep CJ. Gather info and specs and looking for parts. Would like the 2004 or 2005 5.9 CTD but to heavy and strong for the stock frame. Made some calls to Matkins for a Frame but they dont have one that will handle it, was told "It would crack or bend with in a year and they would not cover it. Hope to have the project started this winter when work is slow.