For the kind of money you are thinking of investing I personally would rather spend my cash on the A123 nanotech cells (Link below). More bang for the buck if you ask me. More power, better configuration choices, lite weight, and you can work with them to have a custom pack made just for your project. I have been considering an A123 custom pack myself for an E-bike project, and now you have me thinking about a scooter. It seems more affordable to find a good used scooter CHEAP and then do this conversion like you are considering. Live and learn I guess. This is why I like reading about things like this on our forum. Thanks for sharing your experiences with us.
http://www.a123systems.com/products-...pouch-cell.htm