Gun’Drak dungeon is now open in beta build 8885. It is a five-players dungeon level 77-79 in the region of Zul’Drak. It is ideal for players who wish to level up quick to level 80. It is a fast-paced dungeon that takes about 35-45 minutes with a good team. The four bosses are manageable, with very few trash mobs in between. Definitely shorter than running Zul’Aman.
Blizzplanet has video of the four bosses encounters in the Gun’Drak dungeon.
Gun’drak screenshots here.