I've followed that thing for a while but it doesn't look right for me. The Kinesis Advantage models look appealing if they only had a less extreme layout for things like up/down/left/right. And the price is a bit prohibitive as well.
I guess what I really want is the Microsoft Ergo 4000 with mechanical keys which is probably never gonna happen.
You can remap the keys on the Kinesis Advantage. When I used one, I both remapped the keys and moved the keycaps to get the four arrow keys in one row on the right side. There are mechanical keyboards in more traditional layouts though:
There is the Matias ErgoPro which has mechanical Alps-clone switches. The switches are more similar to the ones used by Apple in the early '90s than to Cherry MX.
There were quite a few models of ergonomic mechanical keyboards made back in the 1990s when mechanical key switches were still mainstream.
However, many of these are rare collectors items these days and are very expensive on the second-hand market unless you find a seller who does not know what he/she has.
The ErgoDox came out of the enthusiast community, and it is not the only one. There have been others in more traditional layouts that never reached outside circles of enthusiasts, and there are several in development.
Some are on the way to becoming commercial projects though: Do look out for the Ultimate Hacking Keyboard in small form-factor with Cherry MX.
Another one with funky layout is the Keyboardio.
Kinesis has also been rumoured to work on a mechanical version of the Kinesis Freestyle
Do expect prices to remain quite high for mechanical ergo keyboards.
Other than those, I would suggest that you try out Microsoft's Sculpt keyboard with low-profile switches. I find the shape and feel to be superior to the MS 4000. It comes with mouse that also has a nice shape but is a bit heavy.