I've seen articles on this in radio control a/c mags - really, the only way is to laminate alternating layers of light/dark wood and start carving and sanding. I've done it before and it works a treat - it's just fiddly and there's no real shortcuts.
Have a look at an RC equivalent of FSM magazine (is there one?), or see if they have a website - maybe they have a forum where someone can post the article in question.
Cheers,
LeeTree