You can do a Hugger style fan for low ceilings, that's 42" - 54" in width. http://www.lumens.com/lapa-hugger-ceiling-fan-with-optional-light-by-modern-fan-company-PAAAAACJNKPDEGCJ.html

I agree with Sweetlake. However, 8' is a standard ceiling height. The blades of a ceiling fan need to be installed a minimum of 7' from the floor. You aren't limited to a hugger type. You can get a standard fan with a short 2-3" downrod. 42"-54" blade span is a good size recommendation.

We have a huge selection of ceiling fans of all styles. http://www.lbclighting.com/ceiling-fans/all-fans.html

Chances are good that you will need a light on it for code in the bedroom. You need at least one light on a switch by the door. In that case, the ceiling hugger type generally looks better unless you find one you like with just descent uplights.