I did a neon version a few years ago, it's about 20 inches in diameter. I've never been able to get a good picture of it because of light reflections, as you can see in the attached .jpg The dot near the center is a dekatron spinning 1 rev/second. Except for the blue LED [indicator for +3.3VDC], everything is neon.
I'm building another one with green neon bulbs; still thinking about cut-out numbers for the hours using green neon bulbs for illumination (doggone it, why didn't anyone make green nixie tubes.....).
If someone is really up to the challenge to make one of their own, I'd be willing to trade a blank PCB for 500 blue neon bulbs.