Guess I'll have to wait until season 8 comes out to find out if they ever revealed Janitor's real name...
(SPOILER)It's iffy. He says his name, or at least you'd think it is, but then three seconds after the conversation he responds to a co-worker who says a different one. So Meh, probably another fake one.
I say his name has to be Neil Flynn, just because of the episode where JD saw him in The Fugitive