If its any comfort to you, the rear brake is really not that essential for normal riding. You can get along without using it at all most of the time. It does come in handy for controlling your speed doing parking lot maneuvers and also when going downhill on loose surfaces, but for riding on pavement I think you could do fine without it, particularly if you work on your front brake skills to compensate.
2004 Rebel 250, 2003 BMW K1200GT (roadburner), 2004 BMW R1200GS(all purpose),
1973 Norton Interstate (in a box in the basement)
1968 Triumph Bonneville