Right now, the ranking system of Halo: Reach is capped just after Lt. Colonel grade 3. Bungie did this so that people didn't sit there and power level all day and make the noobs feel like, well... noobs.
Bungie came out and said that as soon as the community gets together and completes 117 million challenges the level cap will be raised. Why is this news you ask? Because a challenge today, that rewards you 3,000 Cr by the way (a sizable amount), only requires you to link your Gamertag to Bungie.net. Something that many of Halo: Reach players have done since Halo 2 so you can see where this massive jump comes from. You don't even have to play a game; you complete the challenge even before connecting to the server. Bungie's version of trick or treat?
This picture was taken as of 12:30 Eastern time today so expect the level cap to be raised by around 5 or so. I hate to say it, but the 10-14 demographic is going to be the push that players need to get their level goodness on.