I wanted one of these for a long time and finally got a G.M. Parts guy who was cool enough to help me find it. They don't list mirrors individually in their parts system anymore, just by V.I.N. #, so we had to pull 28 part numbers in order to find this mirror. He didn't even know G.M. made this mirror.
Anyway, if anybody else wants one just go to your local dealership and order up part # 15172059 , It will list for $180.78. If you know someone with an account they cut it down to about $135.