Sure. A rigid sidewall could carry part of the load on the tire, which would make the contact patch smaller than it would otherwise be given the pressure. Likewise, elasticity in the tread might make the contact patch a little larger than it might otherwise be. So two different tires on the same rim at the same pressure will have slightly different contact patch sizes, depending on the details of the tire construction. None of these things changes the underlying physics a bit, and none of these things have anything at all to do with the "29ers have a bigger contact patch" myth. Equilibrium demands that the total force pushing up on the wheel be equal to the total force pushing down on the wheel. Period.

If you really want to believe that tires are magic objects capable of defying basic physical constraints, I really don't know what to say. This is the same kind of logic that leads people to buy $100 digital cables for their home audio system.