Thomas Edison once said, "If it ain't broke, mess with it anyway!" Wait, that wasn't Thomas Edison...anyway...
EUREKA! I messed with it one more time. I found a way to make the 20W MR11 bulb (which puts out WAAAY more beamage--more brightly focused--than the standard 20W halogen flood that came with the Malibu light) fit in my system.
I can't wait to try 2 20W MR11's together at the same time, on the road. (One more MR11--$5.)
Ahhh, life is goooooooooood.