I haven't seen anybody else bring this up, but it seems like a pretty obvious correlation to me.
Stormbird:
Blackstar:
Just take off the giant drum turbines and it's a dead ringer, twin tail fins and all.
And another thing, anybody remember the Overlord Airship?
http://wh40k.lexicanum.com/wiki/Overlord_Armoured_Airship
It seems pretty obvious that the Kharadron Overlords are based on that single model. I mean, both are airships being flown by power armored dwarfs produced by
GW.
EDIT: Dunno why I said Thunderbird in the title of the thread.