Oh this is a great idea! I have a Nook too and I have one of those silicone cases but it gets little dirt particles and such stuck to it whenever I take it places with me, which makes it quite an inconvenience. I'm going to bookmark this and have this on my "Once I can crochet I must make this" list.
Kind of a silly question, but here it goes: How did you get the material so even on the shoe (if that even makes sense)? Did you you an exacto knife or something similar after everything was dry to get rid of the excess glue/paper? This is lovely! I have wanted to decoupage a pair of heals for quite some time now! I hope mine turn out as awesome as yours did.