Sam, you know the "dots" for enemies are where you are when the enemy first appeared in your log, right? Which makes it almost useless except for camping?

Re: the OP, there was an addon that did exactly this way back pre-BC. That addon's functionality has since been nerfed. So, no, there's no easy way to do this. Something like Gladiator would work a bit, and Carbonite's punks list does show you everyone in combat log range of you. It isn't perfect, though.