The alternators I refer to are the ubiquitous AC-Delco as came on millions of GM vehicles and are readily available and cheap. They've been retro-fitted to many motorcycles over the years in order to have a reliable source of electricity -- tho, usually in rather rude/crude fitments. The alterantors come in many outputs; but, 60 amp and 90 amp models are common (about 700 watts and 1000 watts).
My friend the founder is a businessman and has many talents and knows the value of his services. Certainly, as expressed by FJRocket, a one-off is going to be costly -- but, if done in some larger numbers, the price goes down considerably. My founder friend once fabricated a swing arm and used available belt sprockets (and belt) to have a belt drive version of a normally chain drive m/c. He cast an adapter to mount a car engine in a m/c using the m/c trans (ala BMVW of years ago).
Suffice to say, this may not appeal to most -- a belt pulley on the end of your crankshaft and a mounting (probably in the way!) for the alternator; but, if electrical power is what's desired? These Delcos have a proven track record -- even among motorcyclists.
What we need is someone to CAD the idea or get in there and work-up something. I personally don't need extra electrons -- but, it sounds like lots do.