Airport Extreme X2 and X4?

Among other rumors floating around the mill looking forward to tomorrow's Keynote Speech, minor details have emerged about upcoming use of 802.11n wireless networking. Found in the MacWorld Conference & Expo PI: Advanced Wireless outlook, the description starts with:

Wireless networking is about to undergo major changes, with 802.11n, or Airport Extreme X2 and X4.

Apple has been rumored to be including the faster "n" soon-to-be standard (up to 600 mb/s), with recent curiosities of the protocol showing up in the latest iMac, MacBook Pro and most recently MacBooks.

Readers also note the recent lack of any availability of Airport base stations on Apple's website, with a refresh to the base station rumored as recently as September of 2006.