My name is Jeff Sullivan. My grandmother was Thelma Rives. She married Jeff Sullivan. Years ago when we would visit them, I always wanted to see the "Reliques of the Rives" book. My father was Richard Eugene Sullivan, and is listed on page 175 of my set. (paper back from Heritage Books, Inc.)
My grandmother often told the story of how this distant cousin, James Rives Childs, came to visit and get his information, which eventually led to her interest in genealogy.
I am replying to your posting to tell you about FamilyTreeDNA.com where you may be able to prove your theory with a simple DNA test. I recieved my test kit recently. The drawback is it is expensive so I have been procrastinating. I am not sure if there is a Rives/Reeves subject group yet, but they can place you in a genetic group going back 25 generations. Let me know if this helps you with your research.