Just to drop my two cents. There is a lesser known engine out there that made it into numerous industrial-use applications and is a fairly frequently harvested block in yards due to their relative high production numbers. Parts are really east to get for them due to a few fleet-providers still holding manufacturer's service tickets on them, etc.
Look into the Isuzu 4bd1T, you Cummins guy's out there will surely be able to attest to how bombproof these things are built, they are common in the Isuzu commercial truck line. Its an in-line 4, turbo-charged direct-injection engine that people like me have been using to stuff into FJ's, Land Rovers and Jeeps for a good long time. There are a ton of forums out there with alot of people talking about how to do this swap as sooooo many have been done already, in soooo many different vehicles. Advanced Adapters will cut bell-housing adapters for just about any application, so bolt-up really isn't an issue....although, yes, the transaxle front end would need to be figured out. (but that is as easy as a straight axle, which is really pretty easy).