Oh man, I don't know. I don't think anyone filmed it at Geek-kon last year. I think she did it at CONvergence, though, so they will eventually be putting that on the CONvergence Masquerade channel on youtube. It's not up yet, though.
Ororo - I think you can pull off a change like that. It would be a matter of constructing the princess gown in easy-to-shed parts. I agree with Empress of Squee, use snaps - the ripping sound of velcro might give the audience the wrong idea! I don't know exactly what the princess gown looks like but I would guess that there's a bodice and skirt that probably can be twirled out of. In that case, go for it.
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