Hardware test successful! SFE runs on both the standard and retina iPads. Now that I’ve switched it to using standard UIGestureRecognizers instead of trying to roll my own in the Cocos2D touches callbacks, the control system works flawlessly.
Once I’d succeeding in getting the controls working, I was very concerned about how usable and intuitive they’d be. My first few games saw me lose miserably to the easiest AI setting, but after a dozen games I progressed to the point where I can occasionally beat the “hard” setting. I’m nowhere near as good with the touchscreen as I am with the cursors (where I can sometimes beat the “insane” AI), but it proves that the touchscreen can work as an input device for this kind of game without resorting to an onscreen joypad.
Needless to say, I’m planning to buy an iCade 8-bitty joypad and get it working with that.