For people who haven't seen the "Dance Dance Revolution" interface referred to in the thread title:
http://news.yahoo.com/s/ap/microsoft_techfestGizmodo was underwhelmed:
http://us.gizmodo.com/gadgets/software/microsofts-dancecontrolled-interface-157705.php
Yeahhhh I'm not too sure about that either. A video would be helpful.
The advantage to the Microsoft device is that it's presumably pretty cheap -- how much hardware do you need to detect a footpress? -- and it sort of makes
any display into a touchscreen (albeit with a 3 x 3 resolution...)
It certainly doesn't make me go "Oooh! Gotta have one of those!" but I thought that was kind of the point of the tech fest, to think outside the box a little...
That touchscreen input system you linked to was cool

-- very
Minority Report. Once you get multiple inputs, you can transform in multiple dimensions simultaneously -- pan & scale, or scale & rotate, etc.
I'm not sure how useful it would be on really large displays -- if the screen is large enough, and you're close enough to touch it, the edges could be out of your field of view.
Something like that could possibly be used
in conjunction with this "Step User Interface" thing, so that moving your hands would do one thing, and moving your hands AND pressing your foot somewhere would do something else....
EDIT: found the StepUI page! all the links are currently broken, though, including link to the video:
http://research.microsoft.com/research/vibe/projects/stepUI.aspx/main Tech Fest 2006 page:
http://research.microsoft.com/displayArticle.aspx?id=1410press release on StepUI. Apparently the "dance pad"
is off-the-shelf (i.e. from a game):
http://www.microsoft.com/presspass/press/2006/feb06/02-28MSRTechFest06PR.mspx