it'd be nice from a nostalgic point of view but surely the way to go is something like the X box ... love or hate M$ how many millions of "normal" people looking for an alternate computing solution would prefer something they can plug a gamepad in one end and a telly in the other? or plug in a keyboard and mouse (dreamcast, anybody?)(hell, 9v batteries and infra-red!) and check your email during the adverts on telly but still be able to hook it up to gizmos and gadgets such as scanners... most people (i do PC admin/virus killing for normal folk) dont run their computers higher than 800x600 anyway as they dont like the writing to get too small on screen... and most tellies nowadays (or is it JUST the sony's???) can handle 8x6 y'know ....
having the keyboard built in just doesnt fit with the way of things... it'd mean getting off your chair to go use it under the telly!