With the introduction of the new levy, the existing excise tax on heavy vehicles will be eliminated effective March 20, 2007
What is this "heavy vehicle tax"? I looked all over the GC web site, without much luck. But this article in the Star says:
the impact of the penalty will be reduced, because the budget states that Ottawa will drop its excise tax on heavy vehicles, which typically adds $500 to $700 to the cost of a big luxury car or full-size SUV.
So, it's even less of a penalty than it sounds.
Another note: The complete list of vehicles eligible for the fuel-efficiency rebate can be found here.