If you have read Jhonen's blog, he doesn't want it back. He stated that Nickelodeon/Viacom have tried to contact him. Although the March reruns have gained enough ratings to be the second highest rated cartoon, there won't be more "Invader ZIM" It came close though! Just Jhonen did not want to be part of it anymore. THOUGH THERE ARE SOME POSITIVE THINGS HE HAD SAID: "...new ZIM stuff is likely not going forward. In this world, that never means never, but it’s not the kind of thing anyone should be holding their breath over!" And he has also said that maybe if some one had "the balls" to step up to work on ZIM, then GREAT! Oh if you want to read more (it's pretty long, but worth reading)
http://www.questionsleep.com/mindspill/?p=2024thanks....
-Ted