Looks to be the same 1U plastic rack chassis I used. It's made by BUD and available from Mouser part # 563-PRM-14460 for $31.60 I believe you'll have to use "straight back solder lug" style TRS jacks to be able to fit them all into a 1U chassis (I have some, but can't recall where I bought them, who made them, etc), not the board-mount Neutrik jacks where the lugs are perpendicular to the jack body.
Ok, so I got off my butt and actually read up on the current schematics/PCB's.
So the Digital board for a 56 input Megadrum is the same as the 32/48 board, firmware for 56 inputs might get posted as soon as next week, any chance an expanded analog board PCB/Schematic might release soon too?