I had an idea like this.
1 person is the hunted
Everyone else are the hunters
The hunted is cloaked except when they attack. They have a slow reload, 2-shot-kill weapon and a 1-hit-kill melee weapon. They are faster, can jump higher, and can possibly climb walls.
The hunters are decked out with chain guns, grenades, etc. They are normal playertypes with a bit smaller of a jump.
The goal of the hunters are to take out the hunted.
The goal of the hunted is to take out the hunters.