Since Wild Bunch is typically limited to the pre 1920 guns, a modern 1911 with all the bells and whistles really isn't appropriate. The good news? There are manufacturers still making 1911s based on the original design and are very very close if not exactly the same as the 1911 original. First and foremost, I point to the Rock Island Armory 1911 "GI" that is manufactured by Armscor and can be had for under $400. This is one of the better bargains in the firearms industry right now if you ask me. Judge bought one a while back and had me message it into a carry gun for him and in stock form, I find it to be an excellent shooter with in tolerance fit and adequate finish. Is it a Colt? Hell no, but at half the price, its a steal. BTW, I just found out that they make a tactical version of this gun in government and commander size and they are still under $500!
Next up is the venerable Colt. You can find an original out there manufactured by Colt, or you can get one manufactured during the war under license by other countries, most famously, the Argentinan "Sistema Colt". Unless you go with a foreign manufacture, the old Colt will set you back a pretty penny. No fears however, you can also buy a newer Colt 1991a1 which is a slightly updated Colt 1911 (80 series firing pin block). Note, some clubs might not allow it, but I couldn't imagine the a-hole that would. There is also a 1911 replica made by Colt mfg.
Next on our shopping list would be the Springfield Armory "Milspec" or "GI". These pistols are top-notch repros and will serve you for a long time and should be allowed at any Wild Bunch match. They'll run you between $500 & $600.
That's about all I have on the 1911 guns available today, there are others out there like Llamas, but this list will get you into a good 1911 that'll do for Wild Bunch, besides, these guns are just a joy to shoot. That's why I've wanted to do Wild Bunch matches for a while.