Gears of War multiplayer problems: where is everyone?

[UPDATE: this appears to be system wide across Xbox Live with other games being affected as well. As several people have pointed out, it could be tied to the imminent Dashboard update. We've contacted Microsoft for some answers.]

This is one of those things we experienced firsthand, and thought "Gee, we wonder if people are talking about this on the internet." We were right. Ah yes, the internet, where everyone (including us) turns to when there's a problem with anything. If you have a doctor who looks up your ailments on Wikipedia, you might want a second opinion.

Anyhow, we downloaded the new Gears of War map pack yesterday, and jumped into multiplayer to get some game on. However, every time we searched for games, usually only one or two would show up. What the heck? Normally you'll have tons of games listed, so there must be something going on. We've emailed Epic for an answer, but until then we remain frag-inhibited. The one or two matches that do show up play fine, but we want some options to choose from.