Is there such a thing as a 5-prong round diamond engagement ring?

my friend is convinced that she once saw and will only settle for an engagement ring with 5 prongs and a round diamond. Has anyone ever seen/heard of such a thing? I find round diamonds in 4 or 6 prongs, and 5 prongs to support a pear or heart shaped diamond, but not what she is looking for. I am not going to propose anytime soon, but still want to be prepared just in case. I have searched the web and always stop and look in every jewelery and antique store I come to, but have never seen this type of ring. Help!