A small sampling from my DIY garage....
My daily driver. Technically a 2wd hybrid - pedals drive one wheel, electric motor drives the other - systems are completely independent. Powered by 2 DeWalt li-ion cordless drill batteries). A real hoot in snow.
For dirt duty...
Built this for my 89 YO Father (Custom frame w/mobility scooter transaxle - powered by Milwaukee 28v cordless drill batteries).