Rusty, I suppose we've completely hijacked this thread by most reasonable standards. However, there's a lot of really good information coming to the surface. Let us know if you want a new thread started on 12V to 6V regulators.
I thought I was grasping the Zener Diode with resistor(s) configuration, but the introduction of capacitor(s) has me scratching my head. Does the capacitor store excess voltage? I'm even more curious about the 3 pin/leg regulator with buoymaker's 'Great regulation' listing.
Could you resident electrical wizards (and you know who you are) walk us through these circuits from the battery to the gas gauge?