Aside from being a great name for an indie band, is there such a thing as a street-legal Zamboni?
Not sure, but Frank Zamboni did drive the Zam down the road to the Iceland Skating Rink when he tested his prototypes…
And from these pictures, it looks like some of them were driven on the roads to the rink. Some of the Zambonis were modified Jeeps.
My son plays hockey and last season he played at Paramount Iceland a couple of times and we saw the restored first prototype in the corner of the rink. Amazing how a So-Cal inventor ended up being one of Canada’s Hockey Gods.
On the site I provided, drop them an email with your question…they would definitely know the answer…enjoy the pics and history of Zambonis too…
Well, it started out as an Impala but ended up a Zamboni. Complete with genuine Zamboni parts, and help from the Zamboni family.
In Ontario, self-propelled road building machines are exempted from having to have plates, and honest to god, we actually have ice roads in the winter ( http://www.mndm.gov.on.ca/mndm/nordev/PDFs/winterroads0304eng.pdf ), so . . . 
If you check out the models available for Zamboni machines at http://www.zamboni.com you can see that the machines lack things like mirrors, seat belts, lights, turn indicators and stuff like that.
The engines are fairly big, but they are running a lot more than just a drive train.