I used Rocketboots and Slow Fall to jump out from the house in Stormwind where you end up when teleporting to Stormwind, aiming almost exactly north.
The results:
I havent been able to recreate this yet, I cant quite remember the exact spot I jumped from.
If you go to that part of the ramp you will notice that there are invisible walls all around you, I managed to get ontop of one. These walls are likely there to prevent players from jumping from the ramp onto rooftops or other offlimits areas in Stormwind.
Standing in that spot will really freak out players who teleport into Stormwind.
I will try to create a guide for recreating this.