I've had a jerry can forever, and wanted to see about adding a carrier to my Gary Lee hatch rack. I did some minimal mods to add a Smittybilt gas can carrier. Pics can be seen here:
http://www.kpcnsk.com/?p=276

Gary makes the best Vanagon specific rear hatch racks. FWIW. He even makes a gas can carrier, but they're pricey and shipping is expensive, considering how rarely I'll actually use it. Still cool, and adds an extra 75 miles or so to the range.

-Jarrett Kupcinski