regggg (don't forget his luvin) and I have been doing some oldschool exploration, and we put two and two together and came up with the following.
If you've been around for a while you'd know these two things, but put them together for an ez thrall kill for alliance or just general lulz bugging the thrall arena event out for a hordie.
Steps:
1) Old way up the back of orgrimmar (hint: pillar, fear, boots, wallwalk, or maybe you're lucky like this guy: hxxp://www.youtube.com/watch?v=wK_njBa4KaQ)
2) Jump into the arena (hint slowfall/ss/rogue/druid)
3) Profit.
This area is totally out of los from outside, however if you have a warlock inside, people on the outside can click the summoning spell.
Thrall appears targettable but I only have horde characters so unable to test this, however if you're horde and buff him or summin' he totally bugs out and sits there for a bit.
Pics: Index of /wow/images/thrall
This was done pre-maint about 5 minutes ago.