I prefer not to use ceiling fans as I have no central ceiling outlet for one in the living room, and because I believe they would look ugly in the dining room and bedrooms. (I don't fancy the idea of lying in bed looking up into a spinning propeller.) Also, I prefer a more passive approach.
I am thinking of something along the lines of a sock (for lack of a better word) that essentially moves the outlet of the ceiling vent to roughly floor level or maybe 1 foot above floor level, something that I can install in the winter (or even only during cold spells) and remove in the summer. The sock could be made of some flexible material that is reasonably air-tight that holds its shape so that air flow is not constricted. The ceiling vents in the rooms with the worst heat stacking problem are next to walls, so the sock could be trained down the adjacent wall and could be made of a color that matches the wall.
Is this a practical idea? Does anyone make such an accessory?