Campaign matchmaking playlists will come to Halo: Reach on Oct. 19, and the game's rank cap should get raised sometime in the month or so, Bungie said yesterday in its weekly update.
Noting that playlist updates are typically on a monthly schedule, Bungie's been doing mid-month updates as well and says the next mid-month edition will feature the campaign matchmaking playlist. Also, "It's our hope to roll out a dedicated Infection and Snipers playlist amidst a slew of other changes."
Regarding the rank cap, right now, everyone's limited to Lt. Col. Grade C, although credits still accrue beyond that rank. When the cap is raised, it's possible some players will immediately gain more than one rank based on how many credits they've earned.
As to that, Bungie notes that 70 percent of the community is at Warrant Officer grade or below, with WO ranks comprising "a long stretch of gameplay," according to designer Luke Smith. "Once you get to Captain it speeds up again." Smith didn't say exactly when the rank cap would raise, just that it would come "soon." In explaining why it was instituted (largely for security reasons early in the game's release), he indicated that the rank cap raise could be tied to some communal challenge.
Lots of other fun details and nuggets of info at the link.
Bungie Weekly Update: 10/08/10 [Bungie]