Moss,
I know your brake idea will turn out great. I also gave this a little thought this weekend while outside working. What I may do as just a simple improvement would be to make a place or mount, on the side of my Rop's to keep a simple breaker bar as in tubing.
I may take the rubber handle off the lever, and just use the breaker bar to engage, and disengage the brake. This way I can tighten the brake lever extra tight to hold, and also get it on and off without any problem. Just take the breaker bar/extention off the mount slide over the handle use, and put back.