I typically do the majority of my questing in the heroic levels and I currently have well under a 1,000 remnants. Although I just did TR Erdrique so I'll be curious to see how many of them get during this life. A guildie and I ran Where There's Smoke on elite with our level 3 TR characters and we encounters about 10 or so champions and we picked up 8 remnants from a single, non-named champion drop. We only had one of the optional names and he unfortunately didn't spawn as a champion.
However, before I did go through my TR with Erd, I took him Devil's Assault on elite and he was level 18 at the time. I was quite surprised to see the number of champion chest drop during the first way of devils. I haven't picked up more remnants in any quest since then (again I haven't hit the epics all that much).
Although I am curious about remnant drops. I had taken a level 20 character into The Lord of Stone on hard (Level 18) and I was picking up remnants from some of the champions in there. I thought this was strange. I have seen this a couple of other times too, so not sure what was going on. (PS-I was only running the quest with my hirelings, level 20 as well, except for my owlbear which was level 17, which makes me wonder if the owlbear got the killing blow perhaps...).
In any case, I don't really have a problem with the reward costs right now because this isn't really an event, although I won't be gathering that many any time soon.