I remember that fic. It WAS on Fanfiction.net at some point, but I haven't reread it in quite some time, so if you say it's not there anymore, I'll believe you. I don't remember the title, though as I recall, the author said that it was supposed to be a series of Psychonauts drabbles, but she (he?) only got around to posting that one chapter.
And Raz was said to be four years old in that story. (Personally, I've long entertained the notion of Raz discovering his powers as an infant, but what do I know?)
Sorry I couldn't be more help; I'D like to read that story again, too.
"This game will blow your mind...out of your nose." - ad for Psychonauts