I am a big fan of diesel engines, and have done two engine swaps in the four wheel world. Several years ago I put a Canadian market Toyota 3B diesel into my gas LandCruiser. More recently, I converted my old Porsche 356 to diesel using a VW 1.6 turbo engine for power. I recently completed a 30 day, 8600 mile coast to coast trip in that car, and it was great fun. Here's a picture of me and the car in Texas on that trip:

I did a travel blog of my adventure for friends and family, if you are interested, you can see it here: http://www.travelblog.org/Bloggers/vonbondo/
I'm not sure yet just what I want to build, I have a 10hp Yamaclone, and may use that to build a diesel dual sport. OTOH, I've always wanted a side hack, and if I decide to go that way I think I'll need a bigger engine!
Cheers to all here, and thanks for the info you've all provided to this site --