What about a wireless keyboard ?
If you have an smartphone, you can control your Daw over wifi for basic controls, as well.
Good idea anyway, although cause I suppose you already owned your controller.
Compared to all of these, the gamepad is absolutely the fastest and most comfortable solution.
I'll demonstrate with a simple scenario:
I'm not satisfied with the take I just did, and I want to do another take from the same place.
1. Hit stop (space)
2. Undo (ctrl + z)
3. Go to the left locator (numpad 1)
4. Hit record (*)
Yes you can do this under a second if you're sitting with a keyboard in front of you. But it's a different story when you're standing up in a cramped vocal booth with a mic stand in front of you.
When I press "L1, X, TRIANGLE, CIRCLE" on the pad, I'm doing the same exact function in a fucking NANOSECOND
...not to mention that I don't have to change my position, leave the vocal booth, reach for a controller or anything. The fact that you can hold the controller in your hand while performing makes the setup super efficient. I can't imagine any way you could be this fast with an iPhone or a wireles keyboard.
Also, since I was the kind of kid who liked to play video games, using the controller is really, really comfortable. You can arm record on different tracks, mute and solo, scan through different tracks, start recording from one place and listen to the take from another etc. Yes, using a pad when you're on your keyboard is totally pointles. BUT if you're a performer, need to be a distance from your computer while performing and haven't got the extra money to pay some dude to push start, stop and rec, using a pad is UNBEATABLE.