That's funny, usually I have sent cooks on other non brewing forums to LHB's to buy GOP's for recipe that cal for it, because it really isn't a common spice to people other than brewers.
You will need to call around to specialty markets, especially ethnic ones, or high end gourmet ones (maybe a world marketplace, if there's one in Colorado, but they might not even have it.).
Is there a big West African community, or african community of any type near you, the spice is really only used in african cooking, and evidently Alton Brown does an okra and tomatoes recipe that calls for it.
I warn you, if you can't find it in a homebrew shop, or an ethnic market you willbe paying big bucks for it. It's really an expensive spice, and therefore if you find it in a high end market you will pay through the nose...but if you find it in an african market, it will cost you less...Kinda like buying saffron...in most stores it is uber expensive, but if you go to an ethnic grocery, like a mexican mercado, you will pay less for it...it may be a lesser quality, but it will work fine for your purposes.