So if you haven't read Dan's blog Hey From Me
Somewhere in the middle of the blog He wrote,
But before the Victorious Christmas episode, you're going to see one of the most insane episodes of TV I've ever written and produced. It's soooo different – I hope you'll find it as hilarious as we all did. I don't want to give too much away, but here's a photo that MIGHT help you guess what the episode's about…
But there's no photo. Did anyone see it before he deleted it. NickUTopia, which is sometimes reliable. Though it is editing by a staff of random NICK Bloggers. posted this blog recapping what Dan said
Then there's this part..
"And finally,
  - Dan is working on a 60/90-minute “iCarly” special that “MIGHT (and I did say “might”) bring back one of the most popular TV Show casts ever! I hope it’ll happen. I think it will .”
So much great news! Who do you think the TV show cast is? Our guess is either Kenan Thompson and Kel Mitchel from “Kenan & Kel” or the cast of “All That,” who recently reunited during the Comikaze convention."