I just found these two images of the Death Star in ROTS:

http://www.wallpapersyrenders.com/fotos/death_star_art1024.jpg

This one might be the death Star in ROTJ though.

http://www.geocities.com/Hollywood/Chateau/9532/rm/sw/ds02.jpg

I also, found this the entire screenplay for ROTS.
http://img58.exs.cx/gal.php?g=pg011rf.jpg
<edit> It seems that there's some images not working in that gallery so, here's another gallery with the ROTS script. If a image doesn't work in the first one it should work in the second one.
second script gallery for ROTS</edit>

Also, a whole bunch of images for the making of ROTS
http://img90.exs.cx/gal.php?g=lucasandhistoys1vc.jpg

Also, some high res pictures of Episode I, Episode II, Episode III, and the original trilogy from the same site.