This will NOT cos :
The 060 may be rather "cool" but not cool enough for a PDA (and it's batteries).
Coldfires and Dragonballs aren't compatible enough to be a big help.
A 060 just hasn't enough power to compete with the next generation of Gameboys.
(No sense to compete with those of today, as those will soon be gone).
The chipset isn't low-power either,and a low-power version would end in
a complete redesign.
The schematics for AA have been long lost (AFAIK).
AA won't look any good against the latest PDA-tech, which even comes with
HW-acceled 3D.
The games aren't on the newest level.
Lot of games will only run on a limited sub-set of all Amigas.
Most games are abondoned,so getting them adapted or just a new
distribution licence would be hard.
None of the companies in this market comes even close to having the
needed $$$$$$$.
What would be possible is selling a high-power-next-gen gameboy with
pre-installed and highly optimized UAE.
Those should be atleast good enough for OCS-games.
