kvale, I like the elegant power set generator, but it doesn't fully solve the OP's question: the power set gives all combinations of a given set, not permutations

That said, I'd also second scooterm's suggestion that giving all permutations in a list is probably the wrong approach from a UI perspective. Especially so if, as the question seems to imply, you're hoping to scale this solution. With 6 columns, even limiting the choices to orderings of 5 or 6 columns gives you an unwieldy 1,440 options ((6 choose 6 = 1) * 6! + (6 choose 5 = 6) * 5!).