I honestly think that the tallest building currently under construction in Michigan may be the new bell tower at Oakland University in Auburn Hills/Rochester Hills. It is 151 feet tall and was recently topped out. Oakland University also has a six story housing building and a six story engineering building under construction along with a new parking structure and maintenance building.
http://www.oakland.edu/elliott-tower
I know there are one or two proposals for apartment buildings in downtown Detroit, but I do not believe that any of them have broken ground yet. We do not get a lot of highrise construction here in Michigan.