New Xbox Live! interface to debut with Forza?

Joystiq tipster, Russell, speculates about the future of Xbox Live!:

"Remember when J Allard gave his GDC Speech? He was using Forza Motorsport to demonstrate the next Xbox platform and how it would integrate with XBOX Live! using features such as a gamercard, customizable music, etc. So is it safe to assume then that Forza will ship with a similar interface like what is shown in the GDC video? If so, will a new version of Live! be released soon or does this mean that there WILL be backwards compatibility? Why would they build a new version of Live just for a demonstration? Makes sense...either there is backwards compatibility or a new version of Live!."

[Thanks Russell!]

UPDATE: This one's been debunked. An inside source has told us that the demo was just that...a demo. It was only meant to show the thinking behind the next iteration of Live!