I think "gated shifting" is over-rated. I've put together lots of custom 9-speed Shimano cassettes with no shifting issues at all. My favorite is a 13 - 26 with cogs from Dura-Ace, Ultegra, and XTR cassettes. It's very light, has close ratios, and shifts perfectly. I've also run 13 - 27, 13 - 28, and 14 - 28 cassettes made from spare parts. They seem to shift as well as the standard Ultegra cassettes right out of the box.