I've heard there's indeed revenue for your content added in the game, but it's not mad amounts of cash. However you certainly do get a special version of the item you created with a "Self-Made" quality, which gets a green name and gets a special sparkling particle effect.
In the case of warpaints, you will certainly get a Self-Made War Paint, and any weapon you choose to use it on will also become Self-Made and will get that special particle effect. Good luck on making a cool war paint for the game!

Thanks Tango.

you get a free copy in self-made quality. You also get paid residuals on key sales.

It can be a lot of money (depending on what your definition of a "lot" is anyway). Warpaints make significantly less revenue than hats, but i'm unsure what a ballpark number would be.