Folding the wing is one way to achieve a necessary change from the landing configuration to the driving configuration. I want a low stall speed in the landing configuration. I want to drive at city traffic speeds into a breeze without generating enough lift to pick up the vehicle or make it unstable. While driving, I don't want to be tipped over by a side gust of wind or the rush of air from a passing vehicle.
OTOH, I'd rather not have to fold the wing, and I invite any suggestions for other means of spoiling the lift.
I like your description of an acceptable roadable aircraft. Why would it be preferable to make the front wheels steerable rather than the rear wheel?
If you don't fold the wing, then you have a severe limit on wingspan, and have to make up for it by extending the chord or having multiple airfoils. My understanding is that the longer the chord, the higher the speed at which the wing begins to stall, so I don't think extending the chord is an option. The Terrafugia Transition has a 27.5' span and a small canard on the nose. To generate the same lift in an 8' span would take at least 4 wings, right?