It's now been announced that there will be a Bob Baker written feature film starring K-9 versus Omega! I must admit that I didn't see that one coming.
To be released in 2017 for K-9's 40th Anniversary.
I live in fear of what this may turn out to be, but at the same time I'm still kind of excited to see it. What if it turns out better than Star Wars Episode 7? Bob Baker wrote The Three Doctors so he owns Omega, but it still seems tricky to write a coherent story without mentioning the Time Lords. The K-9 is a slightly updated version of the one that appeared on the Australian TV spin-off. As long as John Leeson provides the voice he's still the real K-9 for me.
Edit: I'll add that it is official because Bob Baker is writing/producing. Not an official BBC production as far as any announcements thus far.