One little problem: such phones would need a disk or another type of external memory, since the built-in memory is simply to small to contain your list of phone numbers, your mp3s, full 3D games, the pictures you made with your phone, etc. That will probably make them bigger, and IMHO it is not really "handy" to have a cell phone as large as a DS or PSP. With which it is probably easier too make games for that are "working" (the requirement you mention about using one thumb stands in the way). But let's see how the future developments will be.

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