Depends, what do you mean by wild west exactly?
If you mean this...
...with two sets of buildings (or more) with a thoroughfare in the middle, then yes. That would awesome! The problem is I'm sure this would cost 50-60 grand to complete so I would just do a killhouse style CQB.
Or if you have an excavator I like the WWI theme and would be the easiest and cheapest. Trench warfare could be really really fun for paintball depending on how you set it up and what type of games you run. Scenario games with objectives, guys using smoke, this is what comes to mind.
Just an example of a possible game play. 10v10 everyone has either pumps, magfed's (no high cap box mags), or hopper fed with 10-20 round tubes only. Now allow for each side to have a full auto or speedball gun with whatever hopper they choose. Make it to where they can only move if another player has a hand on there back and only that player can shoot (his limited capacity gun) while moving. Once in place the full auto guy must stay at that cover unless moved in the fashion just described.
Basically it mimics a big heavy MG on a bipod that uses a 2 man crew to operate. I can see it now, people scurrying through trenches trying to duck "MG" fire. Risk vs reward do you take the short cut accross the top in no mans land to reach the objective using limited cover on top or do you stick to the trenches methodically moving your way through. I could see a lot of potential.