We have made one brace so far, and we got it installed today.
The final materials we used were 2" x 2" x 1/4" angle iron and DOM1020 1.5" round tubing. We ran into one clearance issue with the the bolt on the passenger side that holds the gas strap in, but that shouldn't be an issue with future ones as we are moving the bend in one inch. However, the brace does clear the interior and allows access to the spare tire. If I had to estimate how much the brace weighs, it's between 5 and 10 pounds.
Here are some pictures after welding it, but before we cleaned it up.
We added the notch on the end, so that way the angle iron could slide under the interior, while still maximizing the contact surface. Overall I think this brace was a huge success. We should be making more this weekend. Sorry for the delay, we've been very busy at work.
Also sorry for the huge images!