From last year's Big Bangs, you might want to try Whipping Boy; there's a fair amount of Rodney in that one, and the plot pivots around him, even though he's not the viewpoint character.

But yeah, it's kind of the luck of the draw as far as who signs up. Last year leaned heavily in a Sheppard direction -- which isn't bad, of course; Sheppard people got a windfall :D -- but it could definitely use a variety of writers!