So my answer is buried deep down there, but I think it's a pretty damn good one. So I'm sharing it with you, my fellow OPPOnauts!
I would pick either a VW or Hilux Camper. Either way, you spend a lot less than a house on the initial investment and use the savings to fund your trip around the world in said mobile abode. In addition, both have parts that can be obtained relatively easy in just about any part of the world. Mechanically simple, reasonably comfortable, and stylish.