We had this issue in our apartment too.
We ende dup putting a console table and resting a mirror on it-- and the thermostat is behind it, then we have other items hung on either side. It looks good and when we need to reach the thermostat, then we just move the mirror forward and adjust it (but we only nee to adjust it rarely, about once every other week, so take that into consideration)
I aslo just saw something on pinterest where the girl took foam board and cut it around her thermostat, covered it in fabric and put it in a frame. Then it was like used as a "pin board" or a cork board, and other frames and stuff went around it. but you could still see the thermostat.
I think it was on the better after blog, if you doa search for it...