I always thought something like this would be a good idea.
Especially for all of those fellows who just bought RC K98kicon's. Might be able to make your rifle's more correct by swapping barrel bands etc.

It might make it more straight foreward (though possibly worse on bandwidth) to have the "looking for bolt" "looking for misc parts" as subforums, in which the threads are divided by firearm type, ie: German, Britishicon, American etc.