Micechat had an interview with one of Disney's animators, Dave Bossert, and toward the end of the interview he talks about the upcoming El Rio del Tiempo makeover with the 3 Cabelleros.
http://www.micechat.com/forums/showthread.php?t=53526
http://www.micechat.com/forums/showthread.php?t=53526
DB: Basically, they’re refurbishing the Mexico pavilion and they asked us to do a new film. You ride on a boat through the Mexico pavilion and there’s a series of, I think, 16 screens. So we’re now telling a little story with Donald, Jose and Panchito. As you go through the ride, Jose and Panchito are looking for Donald. It’s really really fun with some really beautiful animation and it’s nice to be working with some of the classic characters. I think it’s going to open in April or May down in Epcot.