Palindromes -- markets?

I saw a thread on the writing prompts and exercises board about writing palindromes. A friend of mine actually does write them, he's a bit nuts, but they're always fun nonetheless.

I doubt he's ever thought about publishing them, but if I gave him the option it might be something he wants to do. Does anyone know of any markets that would accept such things? Humor was my best bet for placing this, but I really haven't a clue.

Thanks!