Curious on one thing, would it be possible to change the skins in teh replay by either replacing the skin in the skin_x folder or changing the coding of the replay file itself?

I haven't tried it but it this should work.

Make new skin.
Name it exactly same as the one in the replay you want changed.
Save in the skins folder.
Start LfS. It should compress the new skin and replace the old one.

MP3 Astra should know how this works. Because he changed skins in his Blame Game series.