You can build a character that gets 4 daily instances of encounter long Threatening Reach in epic. You'll need Spiked Chain Multiclassing, either the Polearm Master (Fighter) or Bloodwrath Guardian (Warden) Paragon Path, and the Deadly Trickster Epic Destiny. With Bloodwrath Guardian and the Primal Resurgence feat you'll get a fifth instance.
I am not sure that the Luminary Ring adds to your reach for these purposes. You should check that out in the
Rules Q&A.
If it works, I'd probably go with a Dragonborn Fighter|Paladin, Spiked Chain Multiclassing, Lashing Flail Feat, Flail Expertise Feat, Draconic Arrogance Feat.
