A few weeks ago I ran across a thread (Located here, credits to Vuljor: http://www.mmowned.com/forums/world-...hole-taxi.html) that suggested that you could use [Wormhole Generator: Northrend] along with a passenger mount to teleport your friends around Northrend.
**Edit** Only confirmed for Engineer Motorcycle **Edit**
Now Blizzard has a funny sense of humor, the destination for the Icecrown teleport is on top of a very steep cliff. If you take one wrong step without mounting up, you plummet to your death. This is where we'll be killing your friends
First, equip your handy-dandy parachute cloak, and then invite your friend to the group. Tell him you know a cool new trick to teleport friends around or w/e. Put the wormhole down, mount up onto your passenger mount, and have your friend get in. Now click the wormhole, and select Icecrown. This will teleport you and your passenger to the steep cliff I mentioned earlier Immediately jump your passenger mount off the cliff, dismount/parachute cloak, and watch as your friend falls to a very unexpected death!
Now be safe kids, wouldn't want anyone getting hurt!