There is one or two places left in COS that carries a few parts; almost off of the PC stores in the Springs focus on the repair side of the business.
PC Brokers is one that I have used in the past that is still in business in COS. The last time I checked, they did have a few cases, but geared toward price versus expansion.
I don't mind the drive to Denver if there is some place to go and see the computer case in person.

If I see it, touch it - I don't mind buying the hardware local.