Steven,
What colors to use to hid sins probably depends on the nature of the sin. Since I don't think in those terms I haven't given it much thought; I like to choose a color based on what I like. Tell me what types of sins you like to commit and I'll see what I can come up with ;-)!
The seat stay thing is pretty funny. It reminds me of a situation that happened at Masi Carlsbad just after I left. I heard about it a few years later. There were two employees that worked there that were sort of complete opposites. One was quiet and reserved the other brash and cocky. When the quiet guy got his employee bike built, the a-hole type filled the top tube FULL of the angular metal grit that was used as sandblasting grit. That in effect made a solid steel top tube. They plugged the holes in the headtube and painted the bike for the guy. Apparently the recipient didn't notice it! That amazes me he couldn't tell that his frame probably weighted a few extra pounds. Anyway, it was discovered years later when the headset got replaced and the grit came pouring out of the tube! Not a funny story, but sometimes odd things happen when other people are in the shop.
Ironically, your seat stay problem could have been fixed with some paint; any color would have worked. Pour a little in the stay and let it harden and I'll bet the rattle would have stopped!
Brian Baylis
La Mesa, CA