I'm in the same situation, with a Level 20 character who isn't planning on making a habit of epic.
However, to be fair to MadFloyd, I don't believe that this is a 'big nada'. Instead, I believe that he is telling us that we can either run Level 18 quests on Elite or Level 19 quests on Hard and still get the full 20% chance for renown in chests, OR if we want to run everything at Normal, then:
Level 19: 16% chance of renown in chests
Level 18: 12% chance
Level 17: 8%
Level 16: 4%
Level 15: nada starts here, I guess.
So, no those aren't great odds, but it isn't nothing. And notice this doesn't take into account the *size* of the renown reward.