Creating iOS apps on the iPad is an as yet unseen, and largely undiscussed subject. Short of a few forum posts about the matter, I'm yet to hear it discussed in the depth I feel it deserves. This is something that I would genuinely adore, because to be honest, I can't afford an Apple computer yet. I'm certainly not very educated on the matter, I do however understand that Xcode runs on Apple computers with an Intel processor, and so it's probably not going to happen any time soon.
My reasoning is, I have seen a definite push from Apple to prove that the iPad is not simply a device with which to consume media, but also for creating it. Xcode would be such a drastic step in that direction, the only negative I see would be a possible decline in the purchase of their laptop / desktop computers. It needn't be as fleshed out, and probably wouldn't even feature the iOS simulator, but a basic app akin to the scaled down functionality of Garage Band would be brilliant.
Please tweet me with any information / details / speculation on the subject, because as aforementioned, I'm really rather ignorant on the systems in place which would prevent this. I'd also love to hear anyone's opinions to be honest.