rubber-seq.png

SEQ concept using illuminated buttons in place of tact switches/LEDs.

Nice remake of the SeqV4 - adafruit size ?

Yep, the vertical spacing is the standard 15mm, the horizontal is 19mm to align with encoders. The pads would move around less if they were in blocks of 4*3, but strips of 1*4 at least hold together okay in the BLM 16*16 (an acrylic spacer helps).

Just throwing a concept here, nothing's concrete.

Looks fine. Which is the base board board used?

 

Base board? Sorry, I don't understand. It's a new PCB design, you can follow the progress here: