There seems to be a general lack of carrying cases that are avaliable for the cube. Willow Design makes a nice carrying case for the cube with lots of space for a bunch of goodies with it. They used to also make a large case with enough room for a studio display as well. I, however, wanted a case with just enough room for my cube. I do not mind checking my accessories with luggage on an airplane, but my cube is strictly a carry-on cube. I need a bag that is just big enough for the cube.
I noticed one of our custodians at the lab had a niftly little padded lunch bag, almost cube size. I went down to REI and found they sell a bunch of these types of bags. The cube seems to fit nicely in a 24-can cooler. The one I got was an "Artic Zone" Expandable Cooler. It cost me $15, see pictures below:
