Available as an assembled Module and as a DIY project.
This Module is currently available.
Dual 4 channel mixer
The Paperface Dual Mixer is a simple 4 x 2 channel mixer that offers 3 attenuated inputs and 1 single unity gain input per-section. With the option of having 1/4", 3.5mm and banana outputs, or both (depending on how you build the module) allows some great feedback patching options.
These merchants probably sell this module. Huh?