Yeah, coat the foam in tape, especially where you need to bend it, and it is quite strong. Even with paper, putting tape on the outside surface of sharp bends prevents tearing and strengthens things. When bending foam the inside surface of the curve is compressed but the outer portions are under tension, and it tends to rip. When you put tape on it, the tape becomes the outer surface of the bend and doesn't stretch easily, so the foam won't tear and the bent portion is tough. Do some test bends with tape and you'll see that even with very sharp bends, the tape doesn't let the foam tear. You won't be able to do 'ABC' folds as easily with tape, but it can still be done if you lay the tape along the joint, space the boards properly and fold them in using the tape where paper would be with glue on the inside of the joint.