A bill was introduced two days ago to license Home Inspectors. I have not read it thoroughly but will later today. I know bill have been introduced every year for the last five years and seem to have disappeared. The Bill is House Bill 4162 (2009) I think this will get you there http://www.legislature.mi.gov/(S(jta4qk45ewrdxv45xl15ft55))/mileg.aspx?page=getobject&objectname=2009-HB-4162&query=on .
I did see they want to use the NHIE test or something similar.