BRILLIANT!!!!!
I've never had the luck of going to a
MNSSHP, hopefully someday I will, but I love reading this thread for costume ideas.
Last year I was Tinkerbell for just normal Halloween

(not Mickey involved)
it was a home-made costume. (because good luck finding a tink costume anywhere that'll fit an 18 year old!)
here's a photo
i had little white shoes too with bows made out of some leftover green material.
All I did was buy a little white dress at Wal-Mart and then some sheer, sparkly lime-green fabric at Fabricland, and I sewed the fabric onto the dress.
And the wings were really cheap from some costume store.
If I ever get the chance to go to MNSSHP, I'll definatley have to bust out that costume again.