Hello David and Stilla!
We had a 12 volt ceiling fan installed in the bedroom, above the bed. My feeling is that it is pretty wimpy in terms of how much air it pushes. Lying just under the fan, I can barely feel any air movement.
I like the idea of trying to use some 110 voltage for the increase in fan speed.
I asked the installers and they told me they stick a 2x4 or 2x6 (whichever fits best I guess) up in the air ducting (which for us is a molded channel in the styrofoam ceiling). Neat trick!
If you go with a 110V unit, I'd like to hear more about it.
Mike and Mike (Michele)
2004 Alpine 34 FDDS