Another poster pointed out that you can always bid big as the narrator,
which usually ends things quickly. But I find that the players do this just
as often. That is, it's a self-solving problem, that if things are getting
boring, the players will also bid larger and larger to bring things to a
conclusion. The AP system is a pacing system, and as such, people use it to
fix the pace of their contests.
That said, I feel that we're not getting at the heart of your problem. Put
another way: why would you want to have a fixed length for extended
contests? I'm having trouble seeing the advantage to doing so. The AP system
works pretty well, so what is the problem that you're trying to overcome by
making extended contests a fixed length?
Mike