I'd much rather just see an increase in gas tax, mainly because it's much simpler. When you add rebates etc, and laws specifying specific modes of transportation, you're going to end up with a lot of complex law, meaning loop holes. Look at the fuel efficiency requirements on cars. Great idea, but what happens is people by SUVs/pick-up trucks that aren't cars, and we lose most of the advantage. Raise the price of gas and suddenly people become more interested in using less of it. Result: people will not buy SUVs etc because they can't afford the gas. Hybrid cars, buses, bikes, walking, etc all become more attractive. And there's no loopholes in a law like this.
Of course it'll never happen, but I can dream...

Tim