is to bypass the travel sites and just enter "suite hotel, boulder co" in google. Up pops all sorts of hotel options. You can then narrow down further if you want a particular part of Boulder.
I do a lot of hotel booking for groups as part of a side business I have and this is how I always start the search if there's something particular I need. The travel sites are great, too, but I find it takes longer to weed through that way. Once you find a few hotels that fit your needs, you can enter those names into a travel site and see if rates are any cheaper. Often, though (especially lately, for some reason), the best rates are via a direct hotel booking. Don't forget AAA, if you are a member.