OrtharRrith
Active Hunter
Digital509 is suggesting backplate detail, anything really that breaks up the smoothness of the backplate. You may want to consider making it look like you could fit a jet pack to it but choose not to, so pipes, connectors anything sci-fi looking. Of course, if you chose to wear a cape with it then you don't need to go into much if any detail. The advantage with doing a custom is ANYTHING goes!