Sorry to revive an old thread, just found this one via Google while researching the topic. I have to say, I'm surprised at the venom people are spitting at the concept of a gamepad for an iPad (or iPhones and iPod Touches for that matter) - what does it hurt to have one available? It wouldn't be required, just offered to those who would prefer to use them.
I love my iPad and my iPhone, but games that use an onscreen d-pad just annoy me. I can never keep my thumb in the right position, thus sliding off of the d-pad at the most inopportune moments! Sames like Dungeon Hunter, Heroes of Sparta, Street Fighter 4, Mortal Kombat 3, etc... they're practically unplayable to an old-school gamer like me without tactile feedback that a gamepad can offer. Even attaching an iPhone via bluetooth to act as a controller just isn't kosher for me - and I'm willing to bet that a lot of us geezers over 30 feel similarly.
I'm willing to jailbreak my iPad and use my camera connection kit in order to get a gamepad working, though mapping buttons may be a pain without Apple giving their blessing so that many games can offer button configurations legitimately. Hell, Apple could make their own gamepad so there's a universal device developers can count on and tailor their apps for...
Ah well, I've heard the WiiMote can be paired with jailbroken iOS devices for use in various emulators. I may look into that, but I'm not keen on the WiiMote and it lacks the amount of buttons one may need to play anything beyond NES generation games. Better than nothing, though.
C'mon Apple, gaming has been one of your only achilles heels, but you've made a lot of progress in that area since iPhones/iPads hit big. Gamers can net you a crap-ton of money, no reason to snub them - their money is as green as a graphic designers!