Even then we would run into trouble unfortunately. The meshes don't use the same number of textures, they don't have the same number of physics parts (torn cloth, ect) and various other things. I'm not sure if the ps3 repacker is actually a repacker btw, I think it's just an injector. If it was then we'd see much more elaborate skin mods.
I'm not ruling anything out, it just isn't going to be simple no matter how we go about it.
Makes total sense, although from what futuretime has said it's an actual rebuilder and it accomplishes this by reading the entries in the export table and using that to rebuild the xxx package. But based on what you just stated it might be easier to go the other way and replace the expressions instead. If im not mistaken the expressions package and folder contains the move stance and all of the fighters moves so essentially we would be doing an internal swap thus eliminating the need for 2 characters to be used in a fight. Again it's just my theory but i would think that it would probably be an easier method for custom character creation than mesh swapping.