Firstly, I'd like to point out that I do not believe that this is an excellent exploit "as is"; do not shoot the messenger!
Yesterday, on my Monk, I was nearing the cross-realm zone boundary when I used my Roll ability. Shortly after activating my ability, I entered Durotar; several moments after entering the zone I began to see players and doodads until my ability faded. I estimate that I traveled three times as much distance than Roll's normal travel distance.
There is no doubt that the cross-realm zone boundaries can cause many other affects such as the one that I've documented. Because of this, I welcome anyone to take this bug and use it for their own exploit discoveries and post it on the forums.
EDIT: Please move this to the General section if you believe this is "useless".