A small, plastic module with minimal interface (two buttons and 2 digit LED screen) for setting MIDI Channel and polychain settings, that have 4 BS2 voices inside.
MIDI IN and THRU for poly-chaining. Audio IN and Audio Out. Audio In bypass the internal engine and is mixed with audio Out.
We plug MIDI OUT from BS2 to MIDI IN of the module, audio out from BS2 to audio In of the module and have 5 voice poly synth controlled from the BS2 panel and summed audio coming from the last module output. Up to 4 modules can be chained for 17 voices.
Modules have some clips, co we can stack them and have one light, plastic box.
BS2 could have soft MIDI THRU (MIDI OUT mixed with THRU sent on the one MIDI cable) so we can plug a large MIDI keyboard to the BS2 and chain many modules for the proper poly synth experience.
If BS2 desktop is ever released it could too work as a control panel for the modules.
If price was right (c.a. 200gbp for 4 voices) i would be a nice and flexible system:
400gbp for mono, 600 for 5 voices, 800 for 9voices.