This seems to have slowed down a lot. But fear not, I have thought of a plot! (Or, well, the idea for one).
We talked of God-like creatures before, something powerful enough it requires multiple Doctors to stop it. The Impossible Planet/The Satan Pit is one of my favourite stories, and so thought we could do something on The Beast. Of course The Beast has already been slain now but there is still a big question about him we have no answer to. How did such a powerful, god-like creature become imprisoned in that deathtrap on Krop Tor in the first place? The Disciples of Light it was claimed... But Who were the Disciples?
"The Disciples, 12 men from a race thought dead. Together they stand."
The Disciples, you guessed it, would be the Doctors. This could also involve the Master as a secondary villain, possessed by the Beast and perhaps eventually working with the Doctors. I doubt we'll get someone for every Doctor, so not all are required (and I've counted John Hurt there).
Obviously this still needs a lot of work, but please tell me what you guys think!