I can't think of too many other college defensive linemen who've become standout inside linebackers. Lots of those guys become outside linebackers. Not too many end up inside. Matt Millen is the first that jumps to mind. He went from DT to MLB as a rookie with Oakland and won the Super Bowl, if memory serves. Coincidentally, Koa Misi is trying to become another. Though I think what Coyle sees in Misi is not a coverage backer but a hyper aggressive downfield type in the Rey Maualuga mold.
Edit: went back and read a little bit and Bowman was actually a 4-3 outside linebacker known for his speed and pass rushing ability. He wasn't a defensive lineman. Oh, well. That's not nearly as difficult a transition, though he's done well to make himself bigger to take on guards in a 3-4.