Scott McPherson, the wonderful Scottish cover artist for the new Hilaritas Press editions of RAW's work, recently posted some rejected early covers for three titles on his Twitter account, @amoebadesign. Here they are, with the final covers for comparison:
Earlier proposed version of Prometheus Rising cover
Final Prometheus Rising cover for Hilaritas Press
Early cover concept for Cosmic Trigger
Final Cosmic Trigger cover
Early Quantum Psychology cover
Final Quantum Psychology cover
I guess he probably made the right call (I have no information on the possible back and forth with Rasa, who obviously also is a talented artist). But I really like that early Prometheus Rising cover!
The covers, including the alternate versions, would make a pretty cool art exhibition, and also might work as prints.