I'm about an hour south of you (Colorado Springs), and we have a store called Sugarland Sodas. All they sell is cane sugar, glass bottle sodas. I would guess they have 50 to 100 different varieties. At Walmart and King Soopers, we get coke, dr Pepper, orange crush and IBC root beer - all of these high fructose corn syrup.
Here's a link to Sugarland Sodas website:
http://www.sugarlandsodas.com/It's worth the drive. I'm not aware of anything better in the Denver area. If you go, tell Phil that I sent you.