Certainly using flash memory to replace the hard drive isn't a new idea. In the recent publishing of the Economist they did a analysis of the hard drive vs flash memory battle and saids the hard drive industry will be able to keep up w/ the flash. But just a matter of time when the flash industry catches up in technology and cheaper production.
In any case, just a provocative thought. I think it would be totally cool if one day Apple would drop the hard drive replacing it w/ one of their iPods hehehe. Reduced heat, power consumption and even perhaps space. Not to mention no more hard drive grinding hehehe. Maybe i'm just not a fan of moving parts hehe.