From what I've heard and seen, the most popular seems to be the B&M. They have a few styles that will fit. Brian Sargent I know has a 69 with one and it looks like a stock swap...
But, the 68/69 automatic shifters have a not so well known feature, that is kind of nice. If you shift it into low (as from a stop) then when you want to manually shift from first to second you push forward and to the right slightly and it will only shift up one gear, same from second to third... kind of like a ratchet shifter from the factory!