At least two teams have won BCS national championships with Co-DC's (can't remember them off the top of my head).... if that makes you feel any better.
who was the defensive line coach last year? Or is the 2007 defensive line coach just picking up the special teams gig? I'm a little worried about the co-coords also. Hopefully it works out well. I believe OU used this system when Pelini and Stoops were co-coord before Pelini went to be the D-coord at Neb.
Earl Lane will continue as the Dline coach and the new guy will work with the DTs as well. Lane will scheme, etc as usual.