That is a nice idea, although it kills the hope of my suggestion (ability to choose unique gostek just for yourself, so that people could use their own unique gosteks in multiplayer).
But it won't be a problem if more customisation items will be added (different types of shirts, pants, headgears, haircuts, accessories).
On the other hand though, there are more "fair" modders than cheaters. Why take away the pleasure of using some halo mod in multiplayer just because of a few cheaters?
Besides, since right now gosteks are applied to whole teams, player with edited gostek will be affected too. He won't know for sure if he is visible behind sceneries or not, and if the bullets will hit him.
Also, in the end pure skill wins, and even modded gosteks won't help cheaters win.
but I like the idea of keeping gostek (and possibly sounds, weapons and other) as a single file (let's say, a simple .zip, renamed to something like .gtk). Just for sole organization purposes, to reduce the number of files and their size, and keep soldat folders nice and clean.