Daniel Craig draws his six-shooters for Cowboys & Aliens?

Robert Downey Jr. might have just said “Happy trails” to the sci-fi/western flick COWBOYS & ALIENS, but the studio is scrambling to find another A-list actor to wear the spurs and ten-gallon hat.

While his IRON MAN partner vamoosed, director Jon Favreau is sticking to his guns — he and Dreamworks now have their sights on nuBond Daniel Craig, who is currently in negotiations to saddle up for the high-concept project. The movie is eyeballing a summer shoot and a mid-2011 release and naturally, it will be in 3-D. Speculation is that Craig will have some free time while the 007 franchise remains in limbo due to MGM’s current financial anguish.

Although the title is pretty much self-explanatory, the movie involves settlers in the Old West teaming with Apache Indians to fight hostile extraterrestrials. Roberto Orci and Alex Kurtzman (STAR TREK) wrote the script with fellow Abrams-ganger Damon Lindelof (“Lost”).

The project has been endlessly kicking around Hollywood as a pitch “based on a graphic novel” (for about a decade before an actual graphic novel was released).