I fabbed up a new rear brake today, using random scrap pieces from the garage. In total, an old bent 15mm wrench, a Honda S90 kick start lever, and some 1/8"x3/4" flat bar stock and a couple washers.
How many tools does it take to build a brake lever?
I used the stock Trail rear brake rod thingy:
I used an engine kick starter, so that the toe part of the lever could fold up out of the way so that the engine kick starter will clear:
And yes, it works. I took it around the block a few times and I now have brakes (brake) that stops the bike.