I'm not in CO, but here in MT, wildlife, scenic designs, western and native american designs would do well. Montanans (and I'd imagine folks from CO are the same) take pride in our wildlife, scenic vistas, and western culture. Naturally, word art will always do well, from clever bumper-sticker style sayings, religious and inspirational quotes.
Check out the CO tourism website to get a better handle on what they show pride in.
Other products could be magnets, bookmarks, portrait-style cuttings, mini-clocks. Check Etsy and search scroll saw and see what others are selling. That could spark a couple ideas too.