The following interview with Roberto Corbelli lets you see a lot of the pieces inside the upcoming Gold Rush expansion. Corbelli explains how Gold Rush adds economics to BANG! with the gold nuggets and equipment cards they card purchase. He runs through the rules that are in the expansion, as well as the Shadow Gunslinger Variant. At the end of the interview he reveals that Gold Rush will be available in the United States at the beginning of next year. Just a 1000 printing run had been made for the conference. Of interest, he shows all of the character cards. I zoomed in on the video, and have the English for all of the character abilities:
Simeon Picos: Each time he loses 1 life point, he takes 1 gold nugget.
Raddie Snake: During his turn, he may discard 1 gold nugget to draw 1 card up to 3 times.
John McCloud: He may draw the top equipment card from the deck by discarding 2 gold nuggets.
Jacky Murieta: During his turn, he may pay 2 gold nuggets to play an extra BANG!
Madam Yto: Each time a Beer card is played, she draws 1 card from the deck.
Don Bell: At the end of his turn, "draw!" If Hearts or Diamonds, he plays an extra turn.
Dutch Will: He draws 2 cards, discards 1, and takes 1 gold nugget.
Pretty Luzena: Once per turn, she may buy any 1 equipment at a cost reduced by 1 gold nugget.