what i thought would be cool is to see you build an android phone to improve on the many issues found in any mobile phone such as...
battery life
lag due to to many processes
slow wifi connections
one big thing is it doesn't half to run service from a phone company and just do everything off of local WiFi though being able to put service of choice (say trackfone for example) would be nice
another would be enough power to be able to run most common emulators without worry of lag due to most phones having not much ram
some nice features would be blue tooth and a nice sized screen as well as durability
last cool feature would be a custom case for the phone that acts ans a controller with dual analog, d-pad, and six button layout (also this case would be removable)
and just for programming and the controller why not give the classic apple USB connection port for charging and accessories
finally since there really comfortable and compact why not use 3ds analog sticks