Just off the top of my head, and in no particular order:
Vincent Baker, administrator of The Forge and author of Dogs in the Vineyard, In A Wicked Age, Apocalypse World, and others. He's pretty active on his own site and people seem to come to his "place" disproportionately, so anyone's guess whether he'd have time and inclination for this site.
Fred Hicks is a major force behind Evil Hat and their games, and has a significant online presence. He'd probably be interested in SE if he's not already lurking.
Johnn Four writes/edits Roleplaying Tips, which is a big deal.
Berin Kinsman is the big uncle bear of RPG blogging. He may be interested, but not have the time. Worth making him aware of it though, as he seems to believe in community-building. (He kicked off the Ning RPG social network before Ning went sideways.)
Chatty DM is a big, vocal presence online and always has a positive view. Also big on community building, he cofounded the RPG Bloggers Network.
Dave Chalker is a luminary of blogging as cofounder of Critical Hits.
The crew at Gnome Stew, of which there are many, run an influential site. I bet some of them would be interested in hanging out here, if they're not already.
Johnathan Jacobs of The Core Mechanic is the force behind the Open Game Table blog anthologies, as well as a principle mover of Nevermet Press.
Wyatt Salazar/Dennis N. Santana is a vocal blogger who has a lot of name recognition and writes insightful stuff.
Russell "Morrus" Morrissey is the owner and operator of ENWorld.
Brad Murray is the primary author of Diaspora, and is particularly active online.