Actually, I was perusing the official Grubee site looking at the new Skyhawks and they have a 2-stroke pull start motors with cent clutches. This is the direct no BS link to the Skyhawk line.
The pull starts are a little farther down the page, and Motorized Bicycles - Bicycle Motors - Bicycle Engine Kits - Bike Motors - Bicycle Motor Parts
sells the kits for under $300.
I kind of like the looks of them, and they do open another window for different kinds of builds where you don't want the pedals and drive chains connected just to start it.