I'm suspicious as to how likely this is, but if 1UP's sources are to be believed, Natal will not just be a new controller for Microsoft's Xbox 360 but will also be a new console packing the same tech as in the add-on accessory.
Making this suggestion a little easier to swallow, supposedly the 'new' console will differ little from the current Xbox 360 other than the integration of Project Natal tech and a rebranding to reflect that change. Current games will still be playable, though future titles would - unsurprisingly - be able to use the added functionality.
It seems unlikely to me that the hardware in a new 'Xbox Natal' would be any more powerful as owners of the current Xbox 360 would likely be just a bit peeved at developers making their games 'better' on the newer platform. Although I don't doubt Microsoft would love to see old console owners upgrading if it became worth their worthwhile.
According to 1UP, the console will likely be announced at next year's Game Developer's Conference with a launch in July. As I said, I'm sceptical but I'm remaining open minded for now.