im assuming you meant add a top window. in that case:
you can paint ur PSU or put a sticker on it or add a separate window AND light to ur PSU (ive seen it done befor!)
you can add a separate (different color) light to the top half of the case.
round your IDE cables; give your power cables the
"enermax treatment" to make them look nicer (thats what i did).
if you dig thru PC's news archives, you'll find a link to a "make your own plexi res" article. that should help you out if you do plan on making a lexan res.