Suppose a game reaches a theoretical draw (such as a position I could hold while intoxicated playing against Topalov and Anand while they use Rybka), but the opponent wants to play on. Is there a means for ajudication?

no

After 50 moves without a capture or a pawn moving forward, you should be able to claim a draw.

That's sorta what I thought. But, it should not come to this when an opponent is stubborn, but has zero chance to win.