T.C.
This is the same idea as clotheslines- they make thin strips of cork, or metal rails that you attach to the wall. It might work if you could attach it above the chalkboard and have things hang down from it.
I had a couple of cork tiles, and they seemed to be thin and not very dense. Other small bulletin boards I've seen were made out of something denser(not real cork, reminded me more of particleboard), but staples would stick better in it.
Do you have room for an easel?