Hi, I am using todoist on desktop Android and iPhone. My wife recently purchased BB Q10. Do you plan supporting it?
We do not have any strong plans at the moment, but we are always looking to improve and provide the best experience for everyone. So it's very possible in the future.
Feel free to vote on it in our votebox. http://todoist.com/Vote/showProposal/727/ (link is for a general BlackBerry app)