By the power of truth, I, while living, have conquered the universe.
Here's an idea for the epilogue:
The Pillar of Autumn is fleeing Reach as it is getting Glassed, the Seeker of Truth flagship notices and gathers the Fleet of Particular Justice to follow in its wake.
Eventually, they arrive behind the gas giant Threshold and the Autumn begins to see the Halo coming into focus slowly, the scene cuts to the bridge of the Seeker of Truth where you see Thel 'Vadamee and then Keyes & Cortana on the Autumn's bridge.
Then there'd be some awesome one-liner to round it off.