Paul Welday - former Oakland GOP chairman
Norm Shinkle - Ingham County chairman and former State Senator
Dan Tollis - who ran for State Representative
Jack Hoogendyk - who ran for US Senate
Jerry Zandstra

Other people whose names have been floated, but haven't announced include:

John Truscott - former Engler aide
Suzanne Miller-Allen - VP of Sterling Corp
Laura Toy - former State Senator

I personally don't buy the idea that our party is fractured and in trouble.  I also don't buy the media's claims that "GOP Conservatism is dead".  But it's looking like the January state convention is going to be fun to attend.

Lastly, it looks like there's a blog keeping track of the race - Michigan Republican Party Watch.  I found this from MichiganLiberal, which has a clear bias towards seeing incompetent leadership in our midst.