I’m building an art installation with ~4000 HD108 LEDs. Eventually, I want to address them individually.
To start, I want to control them in groups of 40 (100 “pixels”) to play with very fast frame rates.
How would I wire this?
I assume there’s a better way than bridging every signal/clock pad across 40 pixels in a row 
Honestly, address them all now. It’s way less cost and effort than any other way!
Also, why HD108? Have you compared them visually to alternatives? You’ll get slower updates. The only use case I think they’re valid for is .125X slowmo footage, and even then there’s some APA102 variants that are just as good but have faster data transmission. Controller support for 3*16+5GBC bits is nearly nonexistent (you could roll your own), and it would required a pattern engine that also has that bit depth.