Great thought Ferball. Would really help folks on a tight budget.
Was thinking today about a mounting kit, sort of a big erector set so one could make in-frame, rack or front mounts. Would be relatively inexpensive to produce and be all bolt and go. So could be dismantled for new builds. Have a pre-drilled engine plate with the bolt pattern for the widely used engines. Honda/clone (Clonda), HF predator common sized WWs.
An inexpensive kit would be a great gift to the world. A motorized bicycle is whole lotta folk's main or only form of transportation. If there is any way I could be of help with your project, just let me know. Read twice today about members here who when their motorized bicycles failed, they were not in a position cash wise to fix em and were really stuck. Could be the difference between folks getting to work, doc. and to the store etc.
Not sure if it is still true or not but used to be people in Europe were having problems getting China girl kits. So could be a market for you as the engines could be bought locally and cheaply as they are already shipped there or produced locally. So providing all the accouterments for a motorized bicycle would be welcomed, me thinks.
But again, really great thought.