Hi OMF, welcome. There are a few folks from the Island here and I am sure one can advise you. NY is funny about MBs. To my knowledge, the only state where it is just not legal. But there are motorized bicycle manufactures in the city. So, I dunno. I am in no way advising you to break the law but I have yet to meet a peace officer that knew the law concerning motorized bicycles or cared to stop me any way. I used to regularly ride around Poughkeepsie. But was not fun worrying they would. This has come up so often. How about joining forces with other NY MBers and looking into a Petition Spot - start free online petitions at petition spot
Here is a link from here to others discussing NY law. http://motorbicycling.com/f17/new-york-laws-1474.html
I am just north of you in CT, but will be working on the water this summer and may be able to help get some signatures. The time is right with fuel prices and traffic congestion.