Any thoughts on how they will prove Peter's innocence if James doesn't come forward?

I think James will have to come forward. Neal and Mozzie will ask all there "bad" Friends to find him, and Neal will convince him to finally do something good in his liife : tell the truth and prove Peter's innocence ...

I think that Neal and mozzie will find and ask James. but over all I think that they will have to find a different way to prove Peter's innocence, after all Neal has saved his bacon before so he will again.