As you know, I uses future posting quite heavily, which is awesome, as long as I keep to the schedule. Unfortunately, when you have posts two or three weeks in advance, it is actually quite common for you need to post things in a more immediate sense.
And that is just a pain. I just added smart re-scheduling to my fork of Subtext. Basically, it is very simple. If I post now, I want the post now. If I post it in the future, move everything one day ahead. If I post with no date, put it as the last item on the queue.
This is the test for this feature.