Thank you for your reply. Yes, that's what kept me from "connecting the dots" from things mentioned by relatives in my childhood, until I read a comment left on the Cardinal family board by a Mr. Stein, who has Sephardim.com.
Finding an Isaac ben Judah Cardinal, a scholar who Wikipedia says probably lived in France, from the 1100's, also helped dispell any doubts I might have had about the surname. I know they were forced to hide; found too many clues. Also recently found out both sides were of Jewish descent, so they apparently knew enough to intermarry.
What I was hoping for, was some information that someone might have of a family tree with that surname that has more proof of our hidden identity. Again, thank you, I will look up the other reference. Rebecca