4onthefloor/J.S. I looked for a DC-DC converter a while back in Digikey and a bunch of other places that I have forgotten about but no luck finding one that ran at 6V with any where near 5-6Amps. I think you are right though, you could design one easy enough and if done right could be made better than 95% efficient. Just use an adjustable voltage regulator that drove a 20KHz switcher with a cap on the output to get rid of the ripple / audio noise. Probably less than $10 in parts and you could make them with enough capacity to run the radio and guages and they would run cool as a cucumber.
