We went to Vegas several years ago, and the only hotel we found on the strip that allowed pets was The Four Seasons (maybe that has changed though and there are more pet-friendly hotels). Its kind of expensive, but they were SO pet friendly. They had a bowl, bed and homemade treats waiting for us when we checked in. It wasn't a problem to leave him alone in the room, but they asked for a cell # in case there were issues (like barking). They also offered pet sitting services. We didn't do that because Willy was super quiet and never barked or disturbed anyone.
Its a fantastic, relaxing hotel for people too
We felt very spoiled!