Yes, you CAN swap a VW Diesel into a Tracer/Sidekick!
Check out
http://www.acmeadapters.com/store.phpI would DEFINITELY choose a TracKick over a Samurai for a daily driver/mild offroader from a comfort perspective. I drove my
unmodified '02 Tracker 4-door 4x4 from Cottonwood to Prescott, Arizona on unimproved county roads without problems. It wasn't a rock crawling experience but it was difficult nonetheless.
You may want to carefully research the flat-towing process for
any vehicle before you choose. While the Samurai might be easier to rig for flat towing, no vehicle is going to be a simple "hook it up and drive like crazy" flat-tow process.
All you need to know for the Suzuki/Tracker vehicles can be found in the owner's manual. They are widely-used for flat-towing behind a motor home.
I hope that this helps!