Well, here's a quick cut of the UM players that will never beat Ohio State while wearing a UM uniform--I didn't go case-by-case through each recruiting class:
22 commits in the 2004 recruiting class (all)
23 commits in the 2005 recruiting class (all)
13 of the 20 commits in the 2006 recruiting class (7 redshirts still have one last chance). Note that Justin Boren is counted as one of the 13, as he will most certainly use up his eligibility without ever beating Ohio State as a Michigan player.
After 2006: 11 who transferred out or were kicked off the team (Witherspoon, Clemons, Babb, Chambers, Horn, McGuffie, Threet, O'Neill, Wermers, Feagin, Cissoko--there may be more, I did not do detailed research on this either)
Total: 69 (again, by my quick math--didn't go on a case-by-case basis).
This also does not include walk-ons like Nick Sheridan, etc.--just scholarship commits as listed by Rivals.