Found this the other day.. its a mix of model editing and exploit / exploration.
By accident, my model edit did go wrong, and there was nothing but a hole, instead of the undead-starter crypt. I tried to jump down, but i would not stop falling.. and i was moving too!
Im not sure in what way, but this could maybe come in handy for something.
Here is the mpq:
Rapidsharez
On this picture, i jumped to the south, and i flew all the way thru silverpine, til i hit the mountainside wall, and stopped.
Im also going to find out if the same happens with other starting locations, if you remove for example the durotar-cave.