Well, I found a use for extra "unique" cards in Star Wars... make up a few of the cards I don't have!
Now, I have no plans on investing in any of the large ships (which are the only way of getting modifications) or in the X-Wing or TIE expansion, as I have three core sets worth. But I want some of the cards! So... just printed out a few, backed them on the real cards (in the case of modifications I used extra R2D2s and other astromechs) and voila!