I wanted to be able to carry gear on top of my truck, but didn't want to add any more height. I also wanted to leave it on permanently.
I had a rack made that would fit under the existing roof rack. It is 3/4" aluminum with a back-up light attached to it. The gear basket still fits, I have taken it off to get my ski racks on. The cost of the rack was a little over $200 and the shop said they still lost money.
The ski rack is a Thule Rapid Railing with a board carrier and a rack that holds two pairs of skis on it. This works well for me as my skis are more on the edge of the roof rather than in the middle of the roof. I ditched the step rails long ago, so can't get to the middle of the roof easily.
Link to the pics:
http://www.ofoto.com/BrowsePhotos.jsp?UV=407460513954_21124664303&US=0&collid=50152264303 If I had it to do over again, I might make a few changes. Overall, I'm pretty happy with it.