...which was entirely the point when chen pointed out that it won't be easy to make small.

BTW: Pyra's CPU board is separate from the rest of the mainboard (hence also the really bigger size), and a designed by Golden delicious - the guys who make the upgrades for NeoFreenners (GTA4), for Nokia N900 (Neo900), etc.
Meaning that at some point in the future, you should be able to buy upgrades.

Interesting concept to follow.