I searched the net, and this drawing (see page 9) is the best illustration of a misfire alley that I found. It incorporates MR, LMR, and HPR, and minimizes the number of pads that have to be cleared to fly any of them.
I've also collected what this thread has on Misfire alley, and put together the following, which should probably be added to the stagnant FAQ some day:
Bob Kaplow NAR # 18L TRA # "Impeach the TRA BoD" >>> To reply, remove the TRABoD! <<< Kaplow Klips & Baffle:
Save Model Rocketry from the HSA!