Well ! there is a project on prodigy :
the sumthing pcb
Prodigy Professional :: View topic - Sumthing Rev. 2 - Passive Summing PCBs for Sale
the sumthing case by parusha...
Prodigy Professional :: View topic - SUMTHING CASES - BATCH PRODUCTION - ROUND 2
the rest seems very simple.....
I'd be interested in another project if its ever materialized