there is no need for a powered mount because they only work off a lighter socket in a car anyway.
try this:-
http://www.expansys-usa.com/product....asource=123068
I think the Ikea idea is a good one. Get a tall adjustable lamp like this :-
http://www.ikea.com/webapp/wcs/store...ts=10111*10270
Remove the shade and bulb then attach the mount to the top.
Job done