No.
I actually spoke to Tim about exactly that, and while he told me a way of doing it it doesn't actually work. I assume the functionality was there while they did internal testing but disabled for the proper release.
It could be there's a way to access a debug menu in Psychonauts, but I've no idea how. I wasn't really bothered enough about it to press Tim further, but if someone wants to shoot an email off to Double Fine I can't see any harm in that.
