How would I assign an analytic tag to a task?

I don't care about analytic distributions, I want more fine grain reporting under the project analytic account. I don't see any way of assigning an analytic account to a task, or of assigning an analytic tag to the task.

I thought the whole point of analytic accounting was to be able to allocate costs, for reporting? We deal with very large projects, so one analytic account per project is insufficient.