Where you at, Canadian Cripple? I'm in Ontairo and suffer the same problem as you describe, on a regular basis. It is both ridiculous and infuriating - a large heavy product someone might ship for FREE in the USA could cost me $350 to ship across the border, for example.
Where I am, there is a very clever group of Americans running a business called "C.B.I." They are literally 5 minutes across the Ontario/New York border. You use THEIR address to ship your product within the USA, they receive and hold it for you, for a VERY small fee you go pick it up yourself at your convenience, pay your tax to CBSA at the border on the way back - Shazam, you just saved $350 (minus the cost of gas to drive to the border and back which for me is about $50). All legal and legit (as long as you pay the tax to CBSA on the way back... don't cheat on that, they can take your car! ha. True story.)
On larger purchases, where you can often get HUGE price differences from American vs. Canadian suppliers (sorry Canada - I ALWAYS try to buy Canadian first, but what am I gonna do when your prices are routinely 100% more expensive?! Get with the program!!) - the price difference more than pays for the gas, plus you still save the shipping costs.
If you aren't in Ontario... well, then you're gonna have to find a similar company. Maybe call CBI and see if they know anyone else. Google "CBI Niagara Falls." Myself and guys at work use them all the time, they're great.