This a 50 min walkthrough of the design and manufacture of a 350,000 LED display (for a food counter in an airport) - it's interesting, I think, because it highlights various engineering challenges - size, weight, voltage drop, current limiting, static damage, decoupling of electronics from visual design, design of protocols, maintainability, and so on.
https://www.youtube.com/watch?v=9Qlmywxjau0

via hackaday - link to a photo gallery within.



(Each lit arc is about 2m long, containing two meter-long curved PCBs with very many LEDs, and many local driver chips hanging off a one-wire bus. The two PCBs are potted into a carbon fibre surround, I think.)

While we're talking about one-off commercial projects, could anyone share thoughts on how they'd come up with a price to produce a one-off project like this?

I saw this last time I was at Terminal 2, and it was pretty impressive. Had no idea it was Mike's work!

I'd love to work on projects like that. Good budget because its low volume stuff, so no mucking about trying to save a few pennies here and there. Looks pretty too.