Here's one for you. I drove my Trailblazer down to Denton, TX from Tulsa, OK (only about 300 miles) to pick up my mom's Venture that had thrown a rod. Trailblazer is the EXT, 4wd, 4.2 I6. It actually handled it really well and stopped much better than expected with the Tekonsha controller and brakes on both axles. I felt comfortable with the longer wheelbase of the EXT and I believe the maximum towing capicity is right around 5700 lbs. I didn't weigh, but I'm sure I was pretty darn close.
Here's another, but not as extreme. Towing my old 16' runabout with my 2000 Nissan Frontier 2.4/5spd. Never had a problem.
