Dunno if this has enough channels for what you're asking, but the Vixen mixer is pretty close: https://kvgear.com/products/vixen-mixer https://kvgear.com/produ

Dunno if this has enough channels for what you're asking, but the Vixen mixer is pretty close: https://kvgear.com/products/vixen-mixer https://kvgear.com/products/vixen-mixer