I had a thought concerning Dead Like Me - and before you die of shock that there's something besides Doctor Who in my brain right now, the thought actually started with the Time War.
In Dead Like Me, we mostly see the reapers do one soul at a time, but they must get assigned to war zones and catastrophes too, right? That's got to be a sucky job, popping out soul after soul as you watch hundreds or thousands of people dying, and I suppose it's even worse if they're actively killing each other. Perhaps that's an assignment that's only given to experienced reapers. After all, considering the mayhem George can cause with one reap (like in Reapercussions) you wouldn't want her or some other newbie in a highly stressful situation like that.
Then it occurred to me that in the DLM universe, there must have been a reaper (or maybe even two or three) on Oceanic 815. Now that's a drag. Pop out a bunch of souls, and the next thing you know you're stuck on an island with nothing to do but to wait for the next person to get eaten by the cloud monster. Maybe at first you think you're off the hook, no more reaps, but then Post-Its start appearing in your tent... or get washed ashore. If you're really lucky, the survivors may even think you're an Other and kill you, and then get super-paranoid when it turns out you can't die.
After that, I obviously started thinking about which of the reapers we know who'd work best on the island, and I came to the conclusion that it'd have to be George or Roxy, and if we're assuming that the reaper is someone we haven't seen (rather than an AU) definitely George, because Roxy would start bossing people around right away.
The others - well, I love them, but they're too similar to other Lost chars. Rube is cryptic like Locke, Daisy is slutty and materialistic like Shannon, and Mason is a junkie idiot like Charlie. (And it just occurred to me that I like each and every one of those DLM characters better than their Lost counterpart. Go figure.)
There isn't really a George on the island. It could use a George. *g*
The opposite idea is, obviously, if someone on the island turns out to be a reaper, but I have no idea who that would be. Nobody's backstory quite seems to fit. Eko, maybe, if something happened after his flashback that we're not aware of, or Libby (who's certainly a wild card so far). I suppose Sayid might be a possibility too, but that's stretching it rather. So I like the idea of one of "our" reapers on the island a lot better.
ETA: Writing this, I thought, "Someone must have written a fic with this concept." And lookee!
Someone has.