I was thinking about building one of those, but the problem is our output shaft is lubricated with engine oil, and the motor has to be running to lube it. Essentially, if you tow it like that with the chain on it'll fry the output shaft bearings and probably some other stuff.
I bought a trailer from Northern Tools for about $280 and after a day of assembly and a $30 piece of plywood decking it make a fantastic and useful trailer for all kinds of stuff. Plus it folds up nicely and stores easily. To tow the fizzy, I roll it up in the center, put it on the centerstand, strap it down with four straps holding down the lower triple tree, the passenger footpegs, and one on each side wrapping around the frame. I can stand on it and shake it around and it is solid with the trailer, no movement at all. Plus I can tow it with my 4 cyl Camry and I can't even tell its back there!