I'm in the process of reducing my SB depth as well (no fad, just personal preference for aesthetics). I agree with siphoning some out with each water change. Done carefully, you get little suspended sediment, and after a couple months, providing you do regular w/c's, you should have the desired result. Shallow sand beds are nothing new, and dsb's aren't for everyone. As with most aspects of the hobby, there are different ways to accomplish the same thing.