If you figure mid-level as 7-13 or so, well, most of the games I've played in ended at the top end of that range, and my highest-level 3.x player character I think was 14th level when the campaign ended. My current tabletop PC's 500 XP from level 10; I'd like to see him to 11 at least, if only to finish a PrC for the first time (he'd be Wiz [Evo] 5/Cleric [Silver Flame] 1/Silver Pyromancer 5 at that point).