Tonight I saw something interesting at a Wallgreens:

http://www.paperjamz.com/

This is pretty much a step above Air Guitar and one below Guitar Hero/Rockband.

I got to try one and overall they're ok. I like that the freestyle mode is based on the basic chords, but it's rather stiff compared to something like Jam Sessions for the DS.

So yeah, on the upside they're cute; but for the price you might as well get Jam Sessions; it may not be holding a guitar, but it definitively plays like one.