ESCORT DUTY: Military vessels must escort cargo ships the length of the map, preventing raiders from destroying/capturing the merchant craft before they can escape. Of course, you'd need stat sheets for freighters and rules on called shots for disabling engines and/or jump drives.
SPACE ASSAULT: Waves of attackers descend on a heavily fortified space station defended by hordes of fighters. Can the star fortress hold out till reinforcements arrive? For the space station, I envision a typical ship stat sheet--but with no engines or hyperdrive, allowing shields to cover the rear side.
ASTEROIDS: A large fleet must root out a smaller force from an asteroid belt--but resources are precious, and any ship lost will have severe political repercussions (translate this as the large force loses lots of points for any casualties). The playing field is occupied by dozens of planetoids. The rocks all have the same drift, which occurs after ships' maneuver phase. If you're in a hex when the asteroid drifts into it, you take damage and risk destruction.