Just some card ideas that have been bouncing around in my brain, during quiet periods at work.
(These are just rough ideas, not at all tested)
Rattler attack! 6C
Shootout: Runnin' has an additional cost of 2 casualties. The combat does not end until all posses have fled. If all hands in the shootout are lower than Straight Flush, all posses take casualties as if their opponent had pulled a Straight Flush. If the highest hand is a Straight Flush or higher, that posse's shooter gets one permanent control point, and ace this card, ending all of its effects.
(Effectively, this adds a third player to the shootout (the rattler) who always pulls a straight flush. I realise that pulling a SF yourself effectively ties the hand, and so you should also take a casualty, but it had already gotten quite wordy at that point)
Human Shield AC
Shootout: Your opponent chooses: either their next shootout hand counts as two ranks lower, or their shooter gains 1 bounty and their hand counts as cheatin'.
(Do you avoid the hostage, or shoot them?)