if i am correct, you will have to lvl archaeology to max, then stay lots of time in troll ruins to get all the things needed to discover this treasure.
It's impossible to say how long it takes to obtain Zin'Rokh. Here's few things about that sword and archaeology. To get Zin'Rokh as your next solve you need 450 arch skill, no need to be maxed out 525/525.
The way you get your next artifact assigned to you is completely random. After you have gathered enough fragments from digsites around the world to solve the artifact assigned to you, you just cross your fingers and hope next one will be Zin'Rokh. If it is, good for you, most likely it will be one of 14 crap items in Troll line of archaeology. You just keep solving things as long as it takes.
Some people in beta have had Zin'Rokh as their 2nd or 3rd solve after reaching 450 skill, me for example have solved over 30 Troll artifacts after 450 and no Zin'Rokh.
TLDR: It's just luck.
Last edited by Majalahti; 2010-11-03 at 08:15 PM.
Reason: spelling
It takes about 20 hours to reach 450 with 310% flying mount. After that is basically depends on when you get the Zin'Rokh artifact, which is random as mentioned above.