Condensing dryers do not need a vent. They have been used in Europe for years and are starting to make their way here for residential use as well due to efficiency. Moist Humid Air is not introduced to the room. Personally I would let the first few models that are being introduced here sort out the issues before purchasing one.
Here is a nice little article on how they work.
http://laundry.reviewed.com/features...entless-dryers
Here is a small LG unit that is more RV sized
http://www.lg.com/us/washer-dryer-co...nt-load-washer