PSP Phone Mock-Up Pictures
There has been, for as long as I can remember, a rumor that Sony were going to make a PSP Phone. That is, a phone that is also a PSP. Nothing has ever come of it, but every now and then some pictures will surface that suggest what this new device could look like.

The above is yet another attempt at guessing what the device could look like. The article is in Portuguese, but apparently the last part states there is a 35% chance of it being made. Or 0% chance.
While the theory is nice, and if Nokia get their gaming phone back up and running successfully something that Sony might give serious contemplation to, but in the meantime, its very unlikely to happen.
One of the key issues is battery life - phone users don’t want to have to charge their phones every four hours, so until someone comes up with a better, longer lasting power supply, I can’t see this working. Then there is the size. To retain any sort of compatability with the PSP, the device needs that lovely 480 by 272 pixel screen. But its big - too big for phone once you add in the control interface. This isn’t the eighties anymore, no one wants a phone the size of a house brick.
The only thing I can see working is a mini-PSP’esq style phone, with cut down games on a cut down screen, that uses less power and is not compatible with the current PSP system.
They could bring the screen size down without changing the resolution. In fact, the graphics would look much better because the pixels would be smaller.
And like you’ve said, we need a new type of power technology to keep such thing running for one day.
I think this may come true in 10 years from now.