Solutions are everywhere!

There are springy splodgy sticky blobs you can slap on the screen, there's big fullsized controller connectors to wrap the phone in, and there's even wifi touchscreen iPod -> iPad controller things, too.
Plenty to choose from...

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Obviously the Wifi one's the cheapest option.
It's entirely software based, so there's no harm in doing it.
All the end user needs is a ??200 iPod Touch, and a ??400 iPad.
.. Super cheap!

The Fling springy thing is just a sticky splodge that only takes up the space of about 1/3rd of the iPod/Phone's screen.
There's really no excuse to use the entire screen one the player has the ability to twiddle their thumbs in circles to further obscure the screen.
It's excessive amounts of fun to compress your gameplay into a square the size of a 1990s cellphone. That's why they make phone games in tall-resolutions. They're awesome!

And then, of course, there's the third solution.
Those great big chunky blocky splodges that extend your iPod to twice it's size to give you some buttons.
It'll also keep your iPhing nice and charged, and has proper big chunky clickable tappable proper buttons.

You can probably guess which I like best.
The Wifi option is still sodding touchscreen buttons, the Fling is cheap, but unworkable, while the iControlPad seems to "just work".

Would I support it, though!?

Probably not.

If I make a game for my iPhing, it's made FOR the iPhing.
If I assume people would like to use the button version, then I'm assuming my controls are shit. And that's not something I'm happy with.
I've already been through dozens of game ideas and thrown them out due to lack of feasible controls, and the idea of "just giving it a go, because there's always the iControlPad" isn't something I'm happy about doing.
If the controller was in the box with your iPhing, it'd be a different matter.
But assuming people are going to have something extra just isn't something I like dealing with.

Maybe in a couple of years, there'll be a more widespread solution.
It's just not that big of a deal yet.

As for JNKPlat + iControlPad?!?
Sure, that'd work!

But... it'd be shit without one..