What it shows is that a PowerPC system that will sell in the millions (around 20 million for the Gamecube) can be sold for $99 retail and probably still makes a profit.
The Gamecube is too limited for a general purpose computer however (although I had considered it before as a nice AmigaOS platform). Now the XBox360 ... three 3.2GHz PowerPC cores, 512MB memory, Hard drive (SATA), DVD drive (SATA), high end graphics - that'd be a nice hardware platform. Still, it is being sold at a significant loss right now - given the retailer markup it must be at least $200 to Microsoft per console.
I'd rather that the company making this neat A1200 accellerator just made a standard MiniITX sized motherboard, with a full PCI slot and maybe some useful PCI devices like a SATA controller, good audio chip, and so on.
As for PDA/Mobile Phone applications, I think AmigaOS would be a great match.