The Kinesis Advantage uses the same Cherry keyswitches as a Das Keyboard, and has a split ergo layout:
If Microsoft made a Natural keyboard with slightly clacky keys (or even the original Natural keyboard again) I'd buy a couple dozen of them and stay with them for the rest of my life. Unfortunately, the keyboard folks at MS have been doing a poorer and poorer job over the last few years; the most recent ones (from the 4000 up) are squishy-keyed disasters that I can't type on reliably. [Don't get me started on F-lock. What were they /thinking/?]