The Orc Heritage quest has Eitrigg, Ariok, and Thura as representatives of the Blackrock Clan, but they're all on the 'warrior' end of the clan's theme of 'warriors and blacksmiths'.
Maim, Rend Blackhand's brother, supposedly died years ago fighting the Dark Iron dwarves (an odd, offscreen death) while Griselda died in WC2 along with her Ogre paramour Turok... BUT Orgrim was noted in the Rise Of the Horde novel to -like- Griselda unlike Rend and Maim, so there's a good chance he didn't kill Griselda or Turok after wiping out her forces.
Having the Dark Irons drive the Blackrock clan out of Burning Steppes and Searing Gorge and into the Badlands would provide the perfect opportunity to have them both resurface, having been in hiding from Nefarians forces and given up on political power over the years... and instead focused on studying smithing and machinery, providing the avenue to give MU Orcs access to the Tinker class alongside the AU mag'har, and fill out the rest of the Blackrock Roster.