I have an odd idea of seeing Kurt from Glee in the part; it'd be interesting to see him try something weightier.
Might I suggest Carlos Jacott? (For Sorkin, that is.)(Although, weirdly, I've always thought Sorkin was handsome in a "Sears mannequin" kind of way.)
sears mannequin! Love it!
Is there any other answer besides Bradley Whitford, minus mustache?
Matthew Perry? Oh, wait, he already played him.
I think Sorkin should play Sorkin. It would fit with the frequent meta-stuff in his own shows.
Jacott, of course, played either Ricky or Ron (I think Ricky, and Evan Handler was Ron) on Studio 60, so he'd have experience.
That's a Joshua Malina role if I ever saw one.