Hello Guys and Girls,
a few weeks ago, it has been found out in this forums that the "Jeweled Onyx Panther", one of the more expensive mounts, is able to increase your hitbox. I've found another mount that is much more cheap, even if you have to do some quests for it. It's the Amberscorpion - The mount you can get if you are exalted with the Klaxxi.
The steps to get through the wall are incredible easy: Get in the edge, mount on your scorpion, unmount.. and jump.
Tadaaaaaa - You are through the wall and can explore whatever is hiding behind it.
Have fun!
Greetings,
Malfurion