I actually cut them that way, the bends where the corners are used to be the edges of the tool box, i just cut them to the shape i needed with a die grinder then folded over the front edge so it would be blunt and i wouldnt get cut if i ran into it in a hurry lol. No heavy equipment used at all other than the little die grinder and a drill to punch out the holes. They are actually 1 1/8" holes to fit the 1" pipe thru them. You are right though, i have more time than anything else so i put it to good use lol.
Tools required: Grinder with cutoff wheel, drill with hole bits (not sure the proper term lol), tape measure and marker. This can be done with pretty much any old diamond plate tool box or even some 1/8-1/4" thick aluminum or steel sheet metal. Have seen guys use steel also but it is heavier and i was worried the weight might pull the screws out of the wall. Mine are mounted using regular old 3/4" wood screws into the wall. I used the tires to come up with the spacing pattern for the tubing in the plates, just layed a plate flat down and sit the rim on top, then marked where i wanted my pipe to go....i kept in mind that i wanted the back wall to be part of the support so i didnt need 3 pipes, just seemed easier that way. I like seeing people do things themselves instead of store bought stuff.