The only question is, apart from the "cool" factor, what big advantage would a A500 or clone have for use in a robot?
I mean there has been a lot of development into chips for portable devices like ARM-Cored based microcontrollers.
You can get 32 bit ARM7s running at 60MHz for less than $10.....even get Atmel ARM7s at less than USD$3 in bulk.
Not to mention the competition in industrial boards at the moment (just view some of the boards that run Linux reported at
http://www.linuxdevices.com/ )
Don't get me wrong, if you have a heap of existing code or some other reason I'd like to hear about it for robotics but is there much other than the "cool" factor?