We have done similar events, such as a Harasser death race with some specific rules and a +/- point system. Implementing a tournament interface is one of the next advancements we want to make after the in-game overlay is complete.

Your use cases make me want to start working on this now though... all suggestions should be setup like yours

How would you want score to be displayed? On a screen similar to our stats panel by holding a key down to view it? Or maybe a constant non-intrusive overlay?