Was trolling on Nashbar and they have a Schwinn alloy cruiser frame for $24. Shipping is extra but this looks like a great start for a really sweet looking motorized build. Since this is only a frame you have a lot of options for what you put on it.
Schwinn Alloy 7 Comfort Bike Frame - Bike Frames
Schwinn Alloy 7 Comfort Bike Frame - Bike Frames
