Who are the 2 or 3 shoulder joint replacement surgeons in Colorado
most respected by their peers?

You might want to consider using the resources available from "Best
Doctors": http://www.bestdoctors.com/en/default.htm

A one-year internet subscription costs $35 and you can search by your
criteria.

"To solicit nominations doctors were asked, "if you had a close friend
or loved one who needed care and you couldn't handle the case, to whom
would you refer them?" Only those physicians who received a
significant level of positive responses made the "best doctor" list.
[...]
"The Best Doctors in America is considered one of the most widely used
sources of doctor ratings."
Yale Medical Group: 
http://info.med.yale.edu/yfp/best/best.html#ort