I looked at building these this summer. Ultimately I decided I wanted a split keyboard, but didn't want to learn a new ortho layout or spend $300. I ended up buying a Kinesis Freestyle 2, which is one of the few "normal" split keyboards. I liked it so much I bought a second one with the Mac Meta keys, so I still ended up spending $300 anyways, but got two keyboards. What I didn't do was spend an extra $50 on the tilt kit; a few chair leg pads as spacers was enough for me.

I have wide shoulders, bringing my heads together to type all day makes my chest tight and my back hunch. Getting a split keyboard has been my best ergo improvement since a decent chair.