I had Rack Attack remove the factory tracks from my Overland and install Thule tracks and Whispbar racks. Here's the writeup with photos from Rack Attack in Portland, OR: http://rackattackportland.wordpress....whispbar-rack/
I've since traded that Overland for a Summit and am now back to square one as far as a rack goes.
Thule has a new "Aero Blade" system out that I'm interested in. I'd love to see how the 460R and/or 480R towers integrate with the factory tracks.
The custom Rack Attack approach is good, as Moosehead notes, very functional & strong. But the tracks are a little bit wider than the raised section of the roof that they sit on. Just doesn't look right if you're a little bit obsessive about those kind of details. Also, there was no way to remove the bolts that slide on the tracks (to attach the towers) if you want to remove the racks, at least the way mine was set up. I suppose a little dremel work could have fixed that though. if I do it again I'll need to go away while they remove the old tracks and drill for the new ones. Not fun at all.
No rush here this time around. Canoe is stored for the winter and my skis fit in the back just fine when the power starts piling up!