Found this awesome exploit myself and i don't think I've seen anyone else do it.
Even hides your name that is above your head.
Ok,
STEP 1: you want to start by obtaining a hat that turns you into a Gnome pirate. It has a 100% drop rate from this guy and if you head over to him now he will probably have spawned.
STEP 2: Equip it and have fun with your larger mount.
STEP 3: Go to your closest quest giver board in a major city and take this quest(or the alliance version, it doesn't matter which. that takes you to Tanaris (Minimum level of 83.)
STEP 4: Attempt to ride the camel named 'lady something' and it will put you into a cut scene(One that should not be skipped.)
STEP 5: When out of the cut scene you will be invisible but your hat will be showing.
STEP 6: Get killed.
STEP 7: You are now invisible.
Screenshots:
https://i.imgur.com/Ug1ynYN.jpg
https://i.imgur.com/GH2uoQI.jpg