iOS Would anybody be interested in helping me with a external iphone keyboard?

Apple has some kind of program for developing external devices that connect to an iPhone by USB. You have to apply to that program separately from the regular developer program.

I don't think you'll even be able to design it until you're in the programme. It needs some Apple chips in to communicate with the phone, I believe, and the spec is not available until you're accepted.

For information on developing accessories/devices that interface with the iPhone, read up on the Made for iPod program, which all interfacing peripherals/accessories need to go through.