Hard tellin'/ regionalisms

In a conversation with my old farmer neighbour he said, "Hard tellin', not knowin'!" meaning "Its hard to say!" or "I don't really know!" Are there other regionalisms meaning the same thing? I use many of these in my programmes to the delight of both children and adults.
While stranded in the Memphis, Tennessee airport, on our way to the Mardi Gras last year, I overheard a woman reply to a customer, "I know what it say, but it ain't what it is!" She meant, of course, that the product was mis-labeled.
If you have other examples or source materials, and if this is not the place to list them, please e-mail them to me! Much appreciation to any and all.

SR

The Good Lord knows and he ain't telling.

PS. I have several references that list (U.S.) country sayings. The problem is most aren't grouped by subject and don't have a good index. So it's a matter of paging through.