The trainer's name is Annora, and she's in the Uldaman instance in the Badlands.
There is a back entrance to Uldaman in Dustwind Gulch, surrounded by elite troggs. If you can find this entrance it's much closer to her, although you may need to bring a friend; there's an Obsidian Guardian just inside the instance who will be right in your way. I couldn't kill it solo at 45, the way I did it was to freeze trap him, run past him and FD. Beware also the Shadowforge dwarves in the room right beyond.
If you can handle shedding the aggro, or don't mind taking a death for the cause (die just past the dwarves in the hallway, it's fairly safe to rez there if you look out for the bats), you can solo this. I would *highly* recommend being at least level 45 if you plan on doing it solo, because there are eleven scorpions (not elite) in the room where she pops. You must kill all the scorps before she'll appear.
It's really got to be the stupidest trainer location in the game. You'll be glad to get to the point where you no longer need to visit her.
This is a screenshot of where she is: check the minimap for the instance location.
Annora Edited, Fri Apr 21 12:40:54 2006 by Sioux