I like the gardening equipment up high like that. I do something similiar to that. I have several lengths of 1" PVC supported by cowboys and they house fiber sticks, broom, and threaded rod. I can't stock everything but I sure as hell try.
A big John. There is a LOT to be said for being able to find things in your vehicle, especially if you need them in a hurry. One thing I found handy was old (empty) RTV Sealant cartridges, amazing what you can store in them, held to a sheet of ply with 50(?)mm saddles.
Everybody say's that I am a_ _ l about the way that I keep my truck. At the end of the day nothing gets thrown back on the truck. everything goes back in it's place. When I go out to my truck for something, I want to find it right away, I see soms guy's trucks that are a mess. I will post some pics when I get a chance.
Good question, Wireless. In general, the pipes are large enough for the handles to slide in. The one exception is the digging bar; with a chisel on one end, and a tamper on the other, there is no pipe, just the clamps holding it in. In any event, any digging bar makes far too good of a spear in an accident; it's the one thing you want to have held in place!