@Simon Merrett 

No, I'm not planning to use stabilizers. The Kinesis doesn't have any and it doesn't bother me, so I assume it will be the same with the ED.

What about adding a thumbstick mouse pointer movement in the thumbarea?

For the initiated, this looks similar to a dactyl. What's the actual difference? Is it the more aggressive curve to the keycaps in a dactyl?

You've just convinced me to put up a picture without any keycaps. The ErgoDox is totally flat on its own, and the dactyl is curved like the Kinesis (maybe exactly like it). I plan to tent the ED with bean bags under the thumb clusters. The newer version that you can buy outright, the EZ, is designed for adjustable stand thingies that change the various angles.

 
The black keycaps in the pictures are from that Bezos Barn keeb, and the blank colored ones are from a Cherry switch tester. I was putting off keycap ordering until I got it working, which happened yesterday. Woot!

So, 6 follows and 5 likes in almost as many hours. There's perhaps more interest in your keyboard build than you had imagined! 

Thank you for posting the images. Would you mind if I ask some questions about the ergodox design? My most comfortable keyboard is a Microsoft Surface Pro 2 type cover. It's very low profile and is compact, which suits my hands (glove size 9). Moving to an ergodox looks like I'll be moving my fingers over a greater distance. Do you think there's any scope to move the keys closer together on the PCB (I'm happy to rev the board design in kicad) and do you think there would be any advantage in having the keyboard tilted up at the rear? 

Next, key caps - where do you get key cap sets for the ergodox and what profile caps do you like to use? I'm mainly typing code rather than prose and never do gaming. Thanks! 

Coming from the Kinesis Advantage, the flatness of the ED made it seem very large at first. I've only been able to type on it for a few minutes, and only on these borrowed keycaps, but it feels a little better now that it's together. I will say that I have consistently missed the space key in my short trials. 

I think tilted toward the rear would help, as would tenting it by putting bean bags or something under the thumb clusters (my intent).

There are cheap blank PBT sets out there on ebay if you like gray/black/white. The form factor has been around long enough now that you can just search for 'ergo' keycap sets and it'll be the standard 76-key arrangement. For fancier stuff, some group buy designers include ergo sets. You can get past group buy sets and blank sets in both PBT and ABS over at PMK (pimpmykeyboard.com).
I think I am going to go with blank row 3 DSAs in two or three shades of blue or maybe blue/purple, but I can't stop gazing at  these: https://pimpmykeyboard.com/sa-1976-keyset/

Thanks again, that's really helpful. Started my own project to build one - now look what you've started! https://hackaday.io/project/171535-aerodox

PS, do you use / are you planning to use stabilisers on the 2U keys?