A decommissioned Bird of Prey named the I.K.S. Roddenberry, locked in orbit of the remnants of Praxis, would probably do the trick. The plaque could read something like, "In honor of the creator and greatest of all warriors who fought to keep Star Trek alive. Without him, the Klingon Empire would surely have fallen to her foes."
A similar memorial could be placed somewhere in Federation space and for each new playable faction that comes later. All with a theme and plaque appropriate to the faction who's territory it's place in.