We recently bought a second hand 'Dandy' folding camper and are very pleased with it.
Dandy Forum - Dandy Forum
It doesn't use canvas, but is made from double walled pvc with foam insulation in between. This means that it is warm in cold weather and cool(ish) in hot. It also doesn't hold water and be liable to rot if packed away wet. Although I have a 1800cc car, apparently the Dandy will tow quite satisfactorily with 1300cc.
Jim