When I bought my Zero DS last year rebates were not a factor in my decision. I'm getting ready to do my federal and state taxes and it doesn't look like buying an electric bike is of any advantage.
Federal: I'm retired and don't have squat for reportable income or tax liability. My retirement is funded with money I already paid taxes on. Since the federal incentive is in the form of a tax credit you don't benefit from a credit if you don't owe tax.
State of Vermont: Same as above.
Green Mountain Power (my electric company): They offer a dirt cheap installation of a J-1772 charging station but I really have no need as I can plug into 110 and be ready to go in the morning. I have a charge tank but would have to run 220 from my cellar out to the garage. They also offer a $600 cash rebate to new EV owners. I emailed them and got a call today. Explained I had a Zero MC. This is all new to them. They had never considered a MC and called back twice more with questions. Evidently it created quite a stir in their offices. Ultimately the decision was made to not allow me the rebate. It's only for passenger cars. Zeros get zero.

I suspect that their attitude is that a MC is primarily used for fun while a car is for transportation. Never mind that the number of miles I drive my truck was cut in half. I ride every day except winter.
In any event, if my take on the Fed and state taxes thing is wrong please correct me.
Steve