I've been farming Karazhan and Sethekk Halls for a couple months now, at least a couple times a week on each of my 9 characters that are able to enter Sethekk Halls, and once each on 7 of the 9 for Kara, simply because it didn't dawn on me sooner that my lower level toons that were still above 80 could clear Attumen the Huntsman.
I still need Deathcharger's Reins from Stratholme, and an Amani Battle Bear from Zul'Aman, but I haven't bothered to look up Strat since they made it a really low level and a 90 heroic. Zul'Aman I can't quite clear yet without a group, and I have been so busy with Old Mother Tucker that I haven't been doing much other than Kara and Sethekk.
And finally, FINALLY! After months, and actually a year at least on Kara, my hard work was rewarded:
Isn't he beautiful?
I wish he could fly, but he's gorgeous.
I still need the Reins of the Raven Lord from Sethekk Halls, but for now I'm pretty happy.
Happy Mount Farming!