I received my replacement fluorescent light today (I do manage to get a few things done every 6 months or so)
. I went with this light (it's the first one on the page, the 112):
http://thinlite.com/prod03.htm.
I haven't installed it yet but it's amazingly thin (1") and there is enough room for it to fit into the vent area with space available to toggle the switch on and off.
We've had problems with the lenses on the old light fixtures getting scraped up on the roof when we travel, and sometimes falling off. I think this will be much lower profile, so hopefully it will eliminate that problem. And it will use 1/2 the energy of the original incandescent lights.
They're making some really nice LED lights now, but I think that we'd have to upgrade our converter before we switched over to those.