The problem with that
The problem with that is one of basic physics: Heat rises.
Laptop coolers work mostly by virtue of the fact that laptop makers have turned the entire case into a giant heatsink in order to make everything thinner. So there's a lot of heat generating components really close to the bottom of the case, and there's also not a lot of options for where else the heat can go.
The 360 doesn't necessarily work the same way. While Microsoft hasn't officially said anything, the heat problem in the 360 is due to some kind of manufacturing defect. So if you're getting overheating issues, you should make a warranty claim on it. From what I've heard, it doesn't guarantee you'll get back a "fixed" system, but you don't appear to have a lot to lose. Worst case scenario is that you have to live without the console for maybe a month, and then it comes back no better than when it left.