I've looked at the commercial setups available for wingtip lights as well as tail anti-collision lights. Especially considering that my nav lights will be under sealed plexi covers, I think they're mostly overkill and priced accordingly.
I just ordered a few LED automotive lamps from a popular auction site. They will probably take a couple of weeks to arrive from China, but I won't need them for quite some time so it's not a big rush. I bought a red, a green and a big white one. Looking at the nav lights I've seen on certified aircraft, I find it tough to believe that anything bigger than a AAA pocket Mag-Lite would not be bright enough, so I'm not really worried about those. Seeing the monster 120-LED white lamp, though, got me thinking about whether it might not be bright enough for strobe duty. At under $10 I'm willing to splurge just to see what it looks like; if it's not bright enough I'll find some use for it.
I ordered bayonet base 1156 lamps, but the selection seems even better in wedge (3156/3157) bases. I was concerned about those falling out of the socket, but then again I've NEVER seen that happen in an automotive application.
I'll be experimenting with various LED nav/strobe light options while building, should be fun. I'll post results here and in my build log.