Agree on Vertigo in Grand Rapids. Green Light in Kalamazoo is great. Record Lounge in Lansing is nice but small. Not sure how it would compare with Frankenmuth. Ann Arbor - Encore might have the type of stuff you are looking for. Pretty big shop. In Detroit proper - Peoples Records on Gratiot Ave near Eastern Market on a Saturday. They have a ton of rare 80's house, jazz, etc. Dearborn Music is also very big and might have that type of stuff.