It does exist!
Tol'vir sites will be more likely to spawn based on a recent Blizzard update suggesting that if you have solved all rare artifacts for any other race (Night Elves and Fossils will be applicable here), then those races' dig sites will be less likely to spawn, therefore increasing the chance of Tol'vir, Troll and [that one-off Kalimdor anomaly] Dwarven dig sites.
It is possible to have all four Kalimdor dig sites in Uldum.
It will turn heads in cities and battlegrounds - many people will think you found a loophole with your AQ mounts and ask how you did it.
Porting, accepting summons, or logging out while mounted on your Ultramarine Qiraji Battle Tank will see you dismounted on relogging/reloading - I have personally petitioned Blizzard regarding this, so hopefully it has been added to the eventual hotfix development queue for future patches.