Here's my solution- lace this Puch moped hub into my 26" rim using the same 12ga spokes from the 26" wheel.
Should be sufficiently strong for my 79cc build. Already has a BMX freewheel on the bicycle chain side, a bolt-on chainring on the other side that fits a #40 chain fine, and an internal drum brake.
$24 plus shipping on ebay.
You do have to spread the rear frame some to fit the hub width.
Spare parts are available everywhere for the brake and gears.
Looks good. I will fir sure weld a solution. The good thing is that I can use one sprocket even if I want to change the ratio of the gears since I will be using a jackshaft but the rear sprocket have to be perfect. That one is interesting too.