I have the Antec LanBoy Air: http://www.newegg.com/Product/Product.aspx?Item=N82E16811129093
It's not everyone's cup of tea, but I have had good luck with it, and it's quite sturdy and has survived a number of LAN party trips.
I also have this: http://www.amazon.com/Antec-LanBoard-Portable-Computer-Cart/dp/B0041SKBFG
It straps around the case and makes any case portable basically. It's still in the package, so I can't speak to how it is personally. (It was free, as was the case).