I uploaded a variant sequence of play we used to good effect in many plays of ULTIMATUM some, oh, 22 years ago (omigod; 22 years ago). It's in the files section here.

Despite the variant's ancient vintage, I believe it still holds up pretty well in these Modern Times. It's main feature is an interactive game turn that we felt showed ULTIMATUM's best features to to their best advantage.

As I mention in the introductory remarks to the variant, we invariably played the game 3-player, so we always used a spare set of pieces to represent a passive neutral. I didn't include our setup rules for the neutral in the variant file, as they required a bit of component prep (a deck of 37 cards, one for each nation on the board) and a neutral wouldn't be needed when four or more play. If anyone is interested, I can post them in the variant section.