Powertrax No-Slip is definitely an option for a drop-in (the only issue people have are with 2nd gen *open*... search Bansil's posts for more there).

As far a full locker (ie carrier replacement), Peter did make an OX work in his 2nd gen, but it wasn't without problem. I don't remember what the specifics were, but I don't think its a direct fitment.

-Rob