Like in Hockey or many other sports. Raising the banner for the AT winners at a fanfest presentation along with a trophy, either in absentee or to a member present, like the Stanley cup engraved with the winning corporation or alliances names.
These, for Fanfest, would be on display in some area for past winners.
Not really an in game feature though.
Presentation to the AT tournament winners and runners up of smaller banners, in the 4x8" range, as a trophy that can be mounted or hung up on a wall. These would fit easily into the mail for those not in attendance.