I'm a long time fan of the band, and I just joined the forums today to contribute to this topic. I emailed Bleep in July of 2010 asking about any new material and I received this reply:
We are not aware of any imminent releases. However they are still releasing music so something will come along sooner or later!
Kind regards
Bleep Support
Despite the fact that it has been a year and a half since I received that message, I think it's safe to say that Boards of Canada still exists. A lot of people think they have some obligation to their fans to make some kind of statement, but I can think of a few scenarios to justify their silence. They're not the only people doing this either - My Bloody Valentine had a brief reunion and promised new material, but they have been silent for well over a year now. If any of you are familiar with Valve's Half-Life franchise, they have not made even the slightest mention of a sequel to anyone at all despite the community's overwhelming impatience and frustration.
I'm still hopeful that we'll see something down the line, even if it's a decade from now, but for their own sanity, I think fans should try to accept that anything is possible, including no more new material. Fortunately, it still appears that they are making new music. All we can do at this point is be patient, and I'm well aware of how much that sucks. There are plenty of artists who have a similar sound and approach to Boards of Canada, but I think it's stupid and unfair to treat them as substitutes or placeholders. Therefore, I'm just as eager for new material as anyone else, just to give you some perspective on how I feel.