Possible to use a alternator/generator without a battery?

[kipps]

Been dreaming about a project truck powered by a mechanical diesel with an air starter. It would be a thoroughly stripped 4x4, where anything non-essential is gone.

Is there any feasible way for some sort of generator or alternator to self-excite upon engine start-up, regulate it's output within reason, and die when the engine quits turning?

The only demands on the electrical system would be headlights, other exterior lights, gauges, gauge lights, and trailer brake controller. No horn, starter, stereo, or AC.

I've heard of permanent magnet alternators, but I don't think they've ever been used in automotive applications. Does anyone know if this, or some other method would accomplish what I want?