we have a bike room, but I can't imagine most people have a some crazy extra room that you wouldn't want to use for something else.
Yeah, a lot of people make those types of things, heck you could if you were so inclined. They work. They also make special hooks that screw straight to your wall so your bike hanges vertically (tires against the wall for support) if that would be better. If you put them in the corners they would be pretty close to the other wall so they wouldn't just stick out straight into the other room. I'll look for a link of what I'm talking about.