Yes, it's what's used in 'high power' car amps. It's called an inverter, it's a SMPS that basically converts the DC to AC, feeds it through a transformer, and then converts it back to DC again. They generally have feedback from the secondary, to regulate the output voltage.
A LOT though depends on exactly what you are wanting to do, and how much power you need!.
Use a simple bridged amp for car radios. They give about 14W into a 4 ohm speaker with low distortion at clipping. About the same amount of power as an LM1875 or TDA2030 that uses a voltage doubler circuit.
Philips makes more than 76 amp ICs and ST Micro make at least 40. Here is a simple stereo amp from Philips. The datasheets usually have a pcb layout for the circuit.