GetawhaleUsing it for scrims for teams is a fantastic idea, I thought I'd pitch in another idea though.
The mapping community is huge and people make fantastic maps that don't always make it on many servers, so it's tough to get feedback on them and whatnot. You could make your server concentrate primarily on custom maps of all types and formats, as a place for map makers to get feedback and to get their maps really played. It's something that's needed a lot more than you may think. You could go and keep up to date on the contests they are constantly running on tf2maps, and pick 4-6 of them or whatever each time, and publicize your server there, on reddit, here, wherever.
I figure you'll likely go the comp/scrims route, but just wanted to toss this in here too. Maybe someone else can see it and get inspired with their own server.
Those servers pop up from time to time. They're full for 2 days and then no one joins the server because no one is already there so the server just dies.