brophyd

Personally, I'd vote for someone who has the same spirit and flare for the sarcasm and sass that Mr. Owens specialized in, rather than someone who focuses more on 'sounding exactly like him'
 
Speaking of, while I know I could never stand in league with a legend, will there be a chance at an open audition for the position?

Ideally I want it to be someone who can do a really good Gary Owens impression, or at least mimic the essential qualities that made Gary Owens' voice
perfect as the narrator... how he was able to switch from epic-narrator-boom to more intimate-cutting-sarcasm depending on the line.
 
As others have mentioned, George Lowe would be great as he is pretty much the official Gary Owens cover-voice with all his great work on
Space Ghost Coast-to-Coast...
 
I think it's good to have someone imitate the voice... when Mel Blanc died, they didn't change the voices of Bugs Bunny, Daffy Duck, etc. they 
got people who could do the same character voices really well.

You know, Cary Elwes sprung just into my mind. He did fantastic job in Bard's Tale as a sarcastic, snarky bard. His voice work managed to rise a mediocre action RPG into an enjoyable experience.

I think Bruce Campbell would be amazing. :) He does that "endearing sarcastic asshole" thing to a tee.  And like you said, he's a B movie actor -- in other words, a workaholic and doesn't shy away from productions that aren't done through huge studios, so getting him on board might actually be somewhat feasible.