[QUOTE=Finally, please note that Canada Customs will not allow Canadian citzens to drive a US-plated rental car into Canada: "Illegal importation of a foreign car." Yankees & other foreigners--no problem.[/QUOTE]

FYI for Canadian Citizens. Here's a quote from the Canada Border Services Agency website:

Restrictions on temporary importing
If you buy, lease, rent, or borrow a vehicle while abroad, customs law does not allow you to bring it into Canada for your personal use, even temporarily, unless it meets all the requirements and you pay the duties and federal taxes that apply. However, in the case of a one-way rental, you can go to the authorized rental agent closest to your destination in Canada to drop off the vehicle.

The full text can be found at this link:
http://www.cbsa-asfc.gc.ca/E/pub/cp/.../rc4044-e.html