I don't think im being blind - No Stormreaver Clan?
Us Warlocks are always mis-represented *Runs off sobbing.*
It's possible that the Thunderlord crest was initially supposed to be a Stormreaver emblem, since the fel-glow and Gul'dan-style horns and spikes don't fit the Thunderlords at all. That said, here's the basis of a Thunderlord banner -- I'd work Photoshop magic myself, but I don't have a lot of free time right now.