Resolved: Unknown internal alternator fault. I always knew the charging system warning light was pretty useless, but my only prior experience was with a belt failure: just about every warning light on the dash comes on... or worn brushes causing a faint glow of the alt. warning lamp. (actully pretty useful). This time an internal alt failure caused the alt, brake failure, parking brake and lamp failure warning lights to all go dark. Relacing the alternator restored all the lamps. Lesson learned. I wanted to pass it along to those who didn't already know about this third failure mode and what it would cause for symptoms on the warning lamp row. I have already installed an aux. volt gauge.

Thanks to all who responded!