With 3d Printing becoming cheaper and easier to do, 3d printing is becoming a huge part of the RC hobby. Lots of custom parts are popping up everyday. I have started a Thingiverse page at https://www.thingiverse.com/husrto75/designs , please download and enjoy all the designs. The list will continue to grow. Look around that site there are a lot of RC parts free for download.
Also check out these 3d Design groups: