I'd look high and low to find a used one of these...........
Then I'd try to make it street legal as a ""moped"" with lights, horn, blinkers and a 49cc full auto shift engine then after the moped license is applied swap out the engine for a larger one with manual 4 speed or just mod the auto shift engine as far as it can go.
I'd take my chances of a cop not noticing the shift and clutch levers.
Dont know if it could be done for under 1K all depends on the used sikk 125 trail bike price, I have most of the other stuff needed.
This to me would be the best of everything, something that looks cool, fits a grown man, can be ridden on the streets (and offroad) and doesnt need a cycle endorsment because its a moped.(after the mods and inspection)
Its just a dream....it'll never happen.