Smokepole - FYI in 2009, Gov. Ritter signed SB 235 repealing the requirement for folks (non-hunters/anglers) using state lands to purchase habitat stamps (http://www.csmla.org/wildlife/Final_SB_235_Sent_to_Gov.pdf)
There is a provision for "non-sportsmen" to voluntarily purchase a Colorado Wildlife Passport for $25. That said, my local DOW doesn't know anything about the passport and where to buy.

I agree with Saddlesore, Smokepole and the rest in that hunters and anglers are carrying the financial load for the rest of the outdoor recreationalists.