A couple that I met a few years ago at Buses of the Corn in Ontario has an
idea for sotrage of their jack outside of the van. They put it into 4" ABS
plastic, with a cap glued on one end, and a clean-out type acces with o-ring
seal on the other end to keep it water-tight. You have to extend the handle
for it to fit width-wise, so if you do this make sure to measure the full
length with it extended. They store this underneath by the spare tire,
bungied up there, but are working on a better way to hold it up there.

Ed in CT