That would be one long drive shaft. I wonder if the longer length would affect the tow rating ?
I would think that stretched F350 would be almost unmanageable in any situation where you're not going in a straight line or a highway curve. Seems like it would be impossible to make a right hand turn onto any single lane city street. Same for all those mall entrances that make you turn into the parking lot via a curved lane that's lined by a short cement wall or curb.
I know these things aren't meant to be used that way but if you were to use one as a tow vehicle then that would mean trips to Walmart, Grocery stores, etc.