I just got an email from YouTube regarding some old videos of mine that got content-matched by Up Front; the US blackout indeed has everything to do with the new YouTube Red service:
You may have heard that we recently announced YouTube Red - a new membership that offers fans more choice in how they watch their favorite videos with features like ad-free, background and offline viewing for a monthly fee. In order to deliver a great experience for fans who choose to pay for this offering, we are updating our contracts with all of our content partners. The new terms make it possible for us to share subscription revenues with creators, providing an additional revenue stream for them beyond ad-supported YouTube revenue. The overwhelming majority of videos on YouTube are accounted for in our agreements, but there are some partners who have asked for more time to think about their options. While we work with these partners to update their terms, we unfortunately can't make their claimed videos available in the US.
Hopefully Up Front can work out a new deal and get everything working again, especially considering their current overseas marketing push. It makes no sense to freeze out their biggest market outside of Asia.