Ok, took me a little longer than expected, but I did do a bit o' research.. It's plausible and I like the idea, so approved.
If you want a little further reading, I found these two linkies that might (might as in not very, but make for possible addition background ideas) be useful.
http://www.wowwiki.com/Dark_Troll
http://www.wowwiki.com/Shadowtooth