unless you want a docking type solution like oyster, just use something like a DVD case to prop up the rear of the unit, which angles the keyboard comfortably, and gives an extra 1/2" clearance.
Then get I8kFanGui, follow the thread here that provides a fix for the incorrect sensor reading (it's I8k not I9k, so obviously it wasn't originally written for the XPS). I run FGui such that at 116F the fans kick into high and bring it back down to 102F, then go back low. The system will climb back to the 110-112 range usually, but it does depend a lot on the room temp.
The biggest reason I like this setting, is when I do play games, FG essentially kicks the fans into high right at the start, so I know I'm getting maximum cooling, which is important to me since I'm O/C'ing the GPU to 450/375. Stays very comfortable at all times, and didn't have to waste $50 for a useless device that just adds more weight to my bag