Franklin or Tito would be good fights for Bonnar but I'd love to see him fight Thiago Silva. Thiago's rep isn't in the best of shape so a tune up fight could work.
Bonnar wouldn't shy away from a brawl and can take a ton of punishment. I really like Silva but it could be a tough fight for him with the inability to bully his opponent.
Not too mention, they both love to stand and bang