Are you looking for a bicycle rack?
If you happen to be looking for information in choosing a new bike rack, check out etrailer.com. They seem to carry virtually every hitch and roof-mounted rack and in addition to the regular customer reviews, they have 'expert' comparisons of one rack to another, not just the comparison charts that many sites offer.
They also seem to have the best prices on racks and pay the freight on $150.
I'm leaning toward the Thule Doubletrack as installing a roof rack on our Frontier seems too complicated/expensive since a basic roof rack wasn't factory installed.