Cummins makes a 4cyl version of the same engine that is found in Dodge trucks called a 4bt.  It's 3.9L large, and when you turn up the pump the stock version has enough oomph to make about 150hp at the wheels.  Why are we talking about this little 4cyl?  Well read on....

What I'd like to see is a diesel mini-truck, I've used this old Chevy Luv I used to have as an example.  It's pre smog, light, full framed (can handle a diesel's torque), heck when I had it the Chevy ran 14s, and that was with a stock 307 V8 swapped in it.  Instead of my 15mpg V8, I wish I'd put a 4cyl diesel in it.  There was plenty of room (see photo) and it cooled with the larger motor just fine.  Best of all, even with only 200hp, the truck only weighed about 3000 pounds, which means a pretty awesome power to weight ratio.  Sure there are disadvantages such as looks, and the fact that the truck felt like a tin box on wheels.  Still, I think a mini diesel pickup could get 40mpg with proper rearend gearing, and still be fast enough to be fun.  Who wants one?  Who's already built one?  Let us know!