I came up with my own uniform ideas, first Black silk (from story here) with a shirt design like this, but in all black silk, brass buttons, black boots, black silk pants (stretches like spandex), and a gren belt that looks like an x with a green circluiar buckle, and for Awards check out heros of battle.
The Elven Imperial Navy is not as well documented as it should have been. In fact, you will probably get a better game experience if you read the fanon material at Beyond the Moons (the official SJ website). This is really something that could have benifitted from more expansion. If SJ had not been cancelled then I think that one of the SJR series would have given us an expanded description of the EIN (including the location of their homeworld and the mysterious identity of the emporer/empress.)
If I recall correctly, there were some EIN characters in one of the Spelljammer comics, but I think that some fans feel that those uniforms look wrong.