Sure is!
Modding Wiki
Skin Pack
How to Make a Skin Pack
Very cool! I made a test skin but can't get it in-game, I'll have to fiddle with it more I guess. Further dumbfounded by how my "skins" folder is completely empty and yet other skins appear in my inventory.
Does anyone know what "Flex SDK path not set" means? The one google result is on Relic's currently non-existent forums