CA certainly does!
Complete Annihilation is an OTA based mod but our goal is to replace all OTA content and be IP free, so that we can distribute as a free and open-source project.
Since we're open source, any work you'd do for us would have to be GPL compatible (At the moment we are using Public Domain for most of our art, to be as least restrictive as possible on its further use).
We're currently the second largest mod in player minutes, with a large and devoted development team. It would probably help you understanding the designs and units if you play the game, too, so please give it a try.
We've already replaced quite a bit of our content with original work, but its a big project with a long way to go. At the moment we are mostly taking whatever we can get-
Mr.D's remakes,
Azaremoths models, etc.
We've made several efforts towards getting down some concept art, including
work done by my brother (Shraka), some sketches by
Neddie.
We are also taking inspiration for Arm's aesthetic from
PSG TA (Though, not direct remakes- that stuffs still technically copyright).
As for our design goals, its important that designs be partially modular so that players can identify common parts and traits (a weapon type should share a universal barrel appearance) but each unit should be unique enough to distinguish at a distance just from its profile.
If you'd like more info, just reply here, post on the CA site or PM me. whichever you like.