I was really bored a while back and found a way in to the bank which has been thoroughly documented on this website already. However, if you take an alternate path there is another place that you can get.
Experienced explorers might recognize the "edge-of-texture" landscapes that typically denote falling to your doom. This hole in the ground however, allows for some pretty nifty trajectory with slow fall or levitate.
I've frapsed some videos to show you guys how to get down there, because it's a million times easier than trying to explain this in words. So, here you go:
Getting to the hole:
Proper trajectory with Slow Fall:
In case you aren't familiar with how to get to where the first video starts, please reference this link: Stormwind Bank Patch 4.0.3a
Hope you guys enjoy this, and please post if you find anything else useful that you can do with that location!!