I see what you did there with the rock and roll qualification, since the saddest rock and roll song wouldn’t crack the top 100 saddest country songs. But I like bold proclamations.
Mount Rushmore without Hank... the original one... the hillbilly Shakespeare? I can think of several more sad songs from George Jones, but it's your record store. House rules.
I mean yeah, "I'm so lonesome I could cry" should be on there. He basically invented this genre and for the record I put Hank on the Mt Rushmore of most important American recording artists of the 20th century.