I finally pulled this off, whew. It was much more frustrating to obtain than even my ghost wolf. There's a lot of information in this thread and elsewhere, and much of it is pre-patch. It's a bit hard to say what is current and what is obsolete, so let me just detail what worked for me. Though it may seems redundant given all the info in this thread, it may be helpful to someone to have it all laid out:
1. I got the quest on my 84 hunter. I had to do a few prereq quests first.
2. Target the pig.
3. Trap-launch a freeze trap.
4. Pop Berserking.
5. Toss the torch.
6. Cast Tame.
7. Cast Revive, then cancel the cast.
8. Relog.
9. Cast Revive.
Throwing the torch triggers the GCD, and it kills the pig in 7 seconds. With Berserking, Tame was a 7-second cast, so I had to adjust the travel time of the torch via my distance to the pig/trough so the timing all lined up precisely. You cannot spam Revive (triggered the GCD even though I was casting Tame at the time, go figure); you just have to start it precisely when Tame finishes.
When done correctly, the pig falls over dead and instantly despawns without ever displaying the leveled-up graphic. My character pane showed a non-flaming pig, but he was smoking hot when I got back in game and rezzed him.
Thanks to the OP and the other contributors for a really cool pet!