I bought one of these for the camper a couple of years ago.
http://www.google.com/products/cata...a=X&ei=6eNjTsbqM4jfiALfwonPCg&ved=0CF0Q8wIwBA
On sale at the local auto parts for 10 bucks. It came with a mounting bracket, but I never used it because the clip is so bloody handy. It's been beat up, dropped, kicked around and is still going - although the oscillating gears must have finally busted because it quit doing that not long ago. The cord is plenty long to put it basically anywhere in the van it's needed.
It moves a good amount of air. For sleeping on a hot night, I usually clip it nearby and let it oscillate up and down from my hips to my head. Does a better job cooling me off that way than it does just blowing on my head non-stop (what I've been doing since the gears broke). It'll run 24/7 from my 100ah aux battery for 3-4 days before I have to fire up the generator and recharge.
It is noisy. I don't care about that. I can sleep in light or dark, quiet or noisy. Doesn't matter to me. Time to snooze, I snooze. Hell I'm 20% deef from too much rock & roll and airplanes anyway.
Anyway, since the gears broke I've been looking to replace it with a 10" O2 Cool, which have pretty good reviews:
http://www.amazon.com/O2-Cool-Model-1054-Indoor-Outdoor/dp/B000I4L15Q
The one I want is setup to run on 8 D-cell batteries in series (12v) but can also comes with a 120v->12v wall wart. I took one out of the box at the local K-Mart and it looked like a decent unit for 20 bucks. I didn't buy it, because I could swear I saw one somewhere that came with a 12v cigar lighter adapter, and that's the one I wanted.
Then I checked around and found out that the one I saw that comes with a 12v adapter - is the rechargeable version (which has a small on-board rechargeable battery and can ALSO take 8 D-cells):
http://www.amazon.com/O2Cool-1038-Smart-Rechargeable-Swivel/dp/B001RIZEIC/ref=pd_sbs_hg_6
I'll probably end up just buying the one in the store, and ordering the 12v adapter from O2.
http://www.o2-cool.com/faqs.php
(question number 7)