This idea would be very nice as an option to those who want to replace their phone with the pyra. Carrying the pyra next to your ear wouldn't be much comfortable and also looking horrible. Sure, you can use headphones (of what kind ever) to make phoning easier, but that's still not the best solution. You will still have to check the display for who is calling or whatever is happening.
In my opinion you wouldn't have to double/expand the display itself. It would be enough to add a "secondary" screen, like on those ultra gaming keyboards. On those you can push status messages and whatever you want. It isn't neccessary to be able to see the whole pyra screen, information about incoming calls, a contactlist, numpad and so on would be enough for getting the "phone feeling". Depending on the running apps on the pyra you could switch between modes, which will show you e.g. a touchpad or extra keys. This way you don't even have to make this screen too big.
In my opinion you wouldn't have to double/expand the display itself. It would be enough to add a "secondary" screen, like on those ultra gaming keyboards. On those you can push status messages and whatever you want. It isn't neccessary to be able to see the whole pyra screen, information about incoming calls, a contactlist, numpad and so on would be enough for getting the "phone feeling". Depending on the running apps on the pyra you could switch between modes, which will show you e.g. a touchpad or extra keys. This way you don't even have to make this screen too big.