I'm considering a slightly different end game dynamic for the expansion,
which could be used as a variant for the standard game as well:
This way all players will know for a fact whether it's their last turn or not. I'd love to hear your thoughts on this.
4/29/12 Update: The more I play this variant, the more I dislike it for 2 players. I think it's a good idea for 3-4 players though. I do not know if it'll end up in the rulebook or not.