There are plenty of flat spots in the upper Sky Top drainage, but they are rocky, as others have mentioned. In the summer of 2007 I camped alone high up in that valley between Villard and Cairn. But I had a tent and a sleeping bag and a pad.
Besides the pictures on the Southwest Couloir page, there are some excellent pictures of the Sky Top lakes area, as well as a good description of the approach hike, in H2SO4's Cairn Mountain page: http://www.summitpost.org/mountain/rock ... ntain.html
SPer splattski has a great trip report which includes the best beta photos of the SW Couloir that I've yet seen, here: http://www.splattski.com/2007/granite/index.html
splattski has a part of a topo as a pdf file, linked in his trip report, with some routefinding suggestions for the hike past Lone Elk and Rough lakes, and the Sky Top lakes. I urge you to study and follow it. If I had made better routefinding choices in '07 it would have taken a minimum of three hours off of my hiking time both going up and coming down. The choice of which side to pass the several Sky Top lakes on makes a huge difference.
Have a great trip!