I built my own a number of years ago from nylatron and carbon fiber. I got the carbon fiber for free as rejects from a shop in Sandy that made wind surf masts. The nylatron was machined to the OD of the carbon fiber, then had a relief machined to the id and was epoxied in place. male/female threads were cut to create sections that were hollow, but could be screwed together. Emergency supplies are stored inside the staff.
It made quite the kit. Rope saw, space blanket, first aid kit, fishing kit, compass, fire starter kit were all stored inside.
At the time there was some discussion around trying to commercialize the staff, but that fizzled due to lack of funds and other priorities.
I will try to post some pictures of it tonight.