Keep looking around. When I first was told about 770s, it was a deal at expansys. I faffed around a bit but went back later that day to get one, and they had sold out. I looked around the internet a bit more, and found them at play.com so bought one. I know they are all part of the same batch as they came with US power supplies - it is actually against trading standards to supply electronic equipment without a valid plug, but I wasn't going to complain at the price (although I have since seen on forums that play.com refunded up to £5 for an adaptor to anyone that provided a receipt - I didn't bother, the adapter cost less than £1!).

So there are more out there.