I have beatseqr v3.1 unassembled kits available. The assembly is pretty straight forward, with only a couple of weird things you’ll need to do to undo some of the issues I’m reworking for the next version, whenever that ends up being. This version works, and aside from some slightly inconvenient assembly steps, it’s relatively easy work.

Fully built and battle tested with hard acrylic keys, acrylic case & knobs, $349
Kit with arduino mega, $249
Kit with NO arduino mega, $199

kit prices do not include buttons, case, knobs, or cables. contact steve@beatseqr.com for more info.