Then there's also the issue of the PlayKey verb, you'd have to make sure that every instance of PlayKey has another PlayKey after it, to play the appropriate mirror 3do keyframe.
I'm sure
something could be worked out :p
A more depth idea:
Use a program to mirror a 3do, and all the keyframes that would be played on it. Then a program could be made to run through all the cogs that are used in a mod, scan them for PlayKey(), add in the other entry, add variables and whatnots. Then, all that would be neccessary, is for the user to insert a ghost object and a level cog. The ghost object would detect whether the local player/players are near, then create the dummy mirror actor, attach at right pos, and transfer the players velocity to that of the dummy actor. The dummy actor would have the same structured .pup file with the mirrored keyframes, thus, would mimic the correct motion movement animations. Crouch sold seperatly. :p
Geeze, you have no idea how easy that could be coded/VB'd up. I just don't wanna waste my time researching UV crap. I'm so busy with many other things. :p