Nice thread and discussion fellas! I'm living in Berthoud, so I'll watch for your truck crawldit!
I think things might be different in Canada, but in the states, (except perhaps California, where EVERYTHING is illegal) there's nothing specifically "illegal" about having a truck loaded in excess of GVW. Even if you get stopped by the weighmaster, he'll only be checking the tires for a rating and will make sure that you're not beyond that rating. Well, within reason... If your truck LOOKS like it's going to break in half, and the front tires aren't hardly touching the ground, you're likely to be declared "unsafe" and you'll not be allowed to go on, even if your tires can technically handle it.
But the reality is that there are no laws that dictate that you must never load a truck in excess of GVWR, or GAWR for that matter, which would be the more important limit if there was one, it's all about the tires. Next time you're out on the highway, take note of the 1-ton pickups pulling 3 and 4-car transport trailers. They are almost always beyond their published GVW, GCW, and GAWR (at least on the rear!). When they get stopped, the weighmaster just checks the tire ratings and makes sure the tires aren't overloaded.
So what I'm saying is that you should get some sleep, load up to whatever you feel comfortable with, and head out!
And since someone asked earlier, the OEM's MAJOR limitation to GVWR is loaded vehicle handling, as well as chassis durability over rough roads. GCWR is almost always set by rear axle temp to maintain 55mph (or max speed if lower) up Baker Grade (CA headed to Vegas) in 100+F summer heat. Yes, they actually go out and use Baker Grade... I've went on that trip when I worked at Chrysler. 350F in an axle makes the lube REALLY smelly...
