Ok, I see, thinking too high in the clouds. Thank you for the information, though.
It probably would be possible if somebody who actually knew what they were doing (like actually knowing how to flat out program, for example...) were to try, they could probably figure it out.
After all people have made codes for costume specific MotionEtc files, so I think it's possible.
(But most people who could have done it have probably moved on from Brawl modding, to Smash 4 or Ultimate by now...)