Well, I stopped at the hardware store tonight.
A new piece of aluminum, the rest is scrap. The tripod head is the same one that I made the gobo-mount stand for, and it just tightens on the copper pipe. The foam is old computer packing foam, dressed into shape on a grinding wheel and glued onto the aluminum with 3M Pro 90 spray adhesive. The foam piece on the top is a sort of cheek rest. The foam really needs to be covered with something like felt, but this really only has to work once. Think of it as a prototype.
The aluminum is bent to fit my shoulder and back specifically, so it's a more comfortable fit. Makes it look a little weird, but it fits pretty well. It will probably need tweaking.
Also managed a workout by moving a bunch of mamajenzie's stuff up a flight of stairs for an hour and a half. I got a good ass workout in the process. If it weren't total hell on my knees, I'd do this more.
We will see how it works on Saturday. Maybe even tomorrow night. Tonight I'm booshed.