OK, think about it, they show the retina display and lack of home button in the invitation, which makes me curious if there isn't something of more importance to be revealed. And I guess they hint at it in the invitation too: "We have something you really have to see [retina display] AND TOUCH".
Anybody remembering the Senseg "TACTILE PIXEL" technology?
http://cnettv.cnet.com/senseg-demos-prototype-touch-feedback-technology/9742-1_53-50115714.html
Or much more interesting, TeslaTouch, a technology similar to Senseg's, but developed by DISNEY (yes the Disney where Steve Jobs was a member of the board of directors!!!)
http://www.disneyresearch.com/research/projects/hci_teslatouch_drp.htm
Well, if you ask me, we get to feel what we are touching on the iPad.
And in combination with the new AppleTV, which is for sure going to be revealed there too, you have the perfect gaming controller (and mic for Siri) because you could feel the buttons displayed on the iPad.
Going to be awesome!
Probably not going to happen but holy crap that would be awesome