I've borrowed a friend's 360 X-box and have Halo 3 on Live, so if anyone wants to test their mettle against me, look me up. My alias is PorkBellyCow, I'm the pink and purple colored elite.
BTW, as you go up ranks, do you get special abilites and stuff? I've seen people running around with active camo and activating it over and over again without picking up the upgrade.
Xenophobe 01 is my Live handle, Park. I played Halo 3 on a couple of evenings last week. I usually play on Thursdays as that is when I am home alone while the wife is at work.
As for the camo thing... It may be that you were playing a custom game and that was an option. I have not played that many custom games but that would be my guess. Going up in rank doesn't really get you anything but rank. You might see that some people have different armor but those options open up when you unlock achievements (I believe) like finding the skulls on various levels or whatnot.