Well, the most portable tire changing set up is a couple pieces of 4x4 to rest your wheel on, a can of silicone spray lube, and 2 or 3 decent tire irons/spoons. Anything like a machine or fixture will need something to hold it in place against the leverage you would need to exert. I've seen a lot of people raving about the Rabaconda, but I'm not sure how it breaks down for portability.