Besides Colt you mean?
+1 on the USFA.
Even including newly manufactured third-generation SAAs from Colt if "original" means first-generation. USFA seems to be the only manufacturer that is making a deliberate, concentrated effort to reproduce the first-generation SAA. Unless they've utterly failed with their Old Armory Original series, the only thing closer is, obviously, an actual first-generation Colt manufactured back in the day.
Which model is closest to the pic above? Thanks
Wherever you eventually buy your SAA from, you'll want a 4¾" barrel, a cross-pin (or "Pre-War" for the Cimarron) frame design, a color case-hardened (CCH) frame, a CCH hammer, and probably a hard rubber grip. And unless the movie states otherwise or you prefer another caliber, obviously the most common, emblematic caliber would be .45 LC (AKA .45 Colt).
If price is a major consideration and you're mainly after reproducing a movie gun rather than an authentic Old West SAA, then either of the Italian-made SAAs should suffice. Fortunately they both appear to have CCH hammers (not all original Colt SAAs did), which helps in matching the movie gun. Unfortunately, however, their CCH coloration is somewhat lacking throughout, in my opinion, and the walnut grips are not as good of a match. You could get a superior finish for the Cimarron Model "P" for $250 if it's important enough to you:
http://www.cimarron-firearms.com/ModelP/U.S.Finish-Front6Shtr.htm
But hey, it's only money
, and for about $333 on top of that you could buy a superb Single Action from USFA with a similar look but undoubtedly better fit and finish. They also sell models that are extremely authentic to the original, real Colt SAAs of the Old West, such as the US Pre-War (it would cost you, though) and the even more authentic Old Armory Original mentioned earlier (it would cost you very dearly!
).