I'm at work but I've done a few. This guy has some pictures of cover he did for himself. http://www.thecoverproject.net/forums/index.php?topic=7877.0
You need very thick paper to do it on one sheet which can be a little expensive and hard to line up exactly in the center on both sides. I have printed on two separate sheets before but then it is too thick and bunches up in the sleeve of the UGC. I know others have done this because I have seen inlays for some titles posted so maybe they can help out better than me. Here's a link to one of them if you wanna try it yourself: http://www.thecoverproject.net/view.php?cover_id=11493