Re: Where do I start?
You want to build an electric engined bike? Cool!
I don't have much information for you, as I am no engineer. Are you looking to build your parts, or are you looking for an e-kit? I know a guy who would take the former route over the latter (as he loves tinkering on that deep of a level).
I would say check out the suppliers advertised here. I can't remember which ones specifically, but I remember seeing electric stuff on their webpages. Maybe one of them has a kit that would suit your desires/requirements?