This is a copy of the Inside Ride Emachine Free Motion Floating rollers. It looks pretty DANGEROUS, it looks like if you go one inch too far to one of the sides you could fall pretty violently, as in “dude, where’s my face?”
A few years ago I was looking for some kind of bicycle rollers to use my bike indoors during the winter, but I didn’t find much (I went shopping to a few local stores), and the one that I ended up buying was missing parts, so I ended up returning it. It sounds like a good idea, but I’ve been always afraid of falling on my face, I’m allergic to pain.
Go to http://www.instructables.com/id/DIY-Free-Motion-Cycling-Rollers for more info.
If somebody comes up with a safer machine let me know :D.