I have this rack and love it. Easy to install, can fit up to 4 bikes on it, doesn't take up too much space. It pressure mounts between floor and ceiling. I put extra felt pads on bottom to ensure it didn't scratch floors. I have had it in small apartments in NYC and Seattle and has been pretty much the perfect solution. If space is really an issue, and you could drill in the ceiling (sounds like you can't but IF), you could go for a ceiling mounting solution, which is how my wife and I have our tandem hung.
http://www.amazon.com/gearup-OakRak-...bike+rack+wood