Imfung, that's useful information, especially as United is a joint venture partner. I haven't seen anything about that on FlyerTalk.
If you haven't got the final 2 squared away yet (that wasn't clear to me) see if you can get them rebooked on Asiana via Incheon. They're a Star Alliance partner, and it's not a huge roundabout route. And once those two tell you about their experience you'd be so jealous! :)
Seeing as United has also had to cancel (postpone) DEN-NRT and other new/restart routes (as the planes are needed to cover the 787), I wonder how they are working with their partners. They're going to need ANA cover for SFO-TPE which is one of the routes postponed.
Well done for your persistence, and look on the bright side. You'll get 100% mileage and elite accrual in MileagePlus now you're on United metal, instead of only 50-70% on ANA. :)
Edited: 12:43 am, February 27, 2013