What you'll need:
1) Ogre Suit, Nog Elixir, Druid form -- Some disguise that:
A) Can be used in combat.
B) You CANNOT mount in.
2) Hearthstone set to Shattrath or Quel'danas OR a summon. (You can use the summoning stone if you like.)
How it works:
You're going to need to go to the Wetlands.
Due north of Menethil Harbor is a pirate ship staffed by cursed sailors. Go there.
Before engaging them, transform into your NON-MOUNTABLE disguise.
Engage them. Probably best to let them do the hitting at 70.
You'll get a debuff which transforms you into an undead for two minutes.
Finish the mobs off once they place the debuff on you.
At this point, hearth or accept a summon to Quel'danas. (You can go through Shattrath if necessary.)
Race to pick up the quest "Distraction at the Dead Scar" and, with around ten seconds left, hop on the mount. You can do this as long as the undead debuff is still up.
Shortly after going airborne, the debuff will fade.
This will result in you standing/riding the dragonhawk in your disguise/druid form.
Logout quickly. (Should be instant on the flying mount.)
Log back in. The game will reapply your buffs. However, the costume buff comes first. Meaning the game's attempt to remount you fails.
From here, you are dismounted and flying along the Dragonhawk's normal flightpath.
However, you will be traveling MUCH lower and MUCH slower, swimming in your disguised form.
You can dismiss the disguise if you'd rather be doing this in humanoid form.
The quest is already easy but this makes it absurdly easy as you slowly and leisurely swim over the Dead Scar, tossing arcane charges casually. Other players will pass you on dragonhawks, noting your graceful flight... but no matter how crowded your server is, you should easily complete the run in one sweep.
And everone gets a glimpse of you soaring through the air. Who needs a mount?
And if a GM asks you about it, remind them that your mission is to create a DISTRACTION at the Dead Scar! What better distraction than a flying Ogre/Boomkin/Skeleton lobbing arcane charges.
Surely, the Shattered Sun Offensive would be proud of your ingenuity!!!