SilverWook said:
The Revenge poster is perfect for the back cover. Never seen that variant of the 1985 poster art before. I think these two are more iconic though...
http://www.theforce.net/collecting/posters/rotj/style-a.asp
http://www.theforce.net/collecting/posters/rotj/style-b.asp
I don't know if textless versions are out there.
Can't recall if Style A was ever used for a VHS or LD release. I think that would be a cool choice for the front cover. I really do like Style B as well.