Available as an assembled Module and as a DIY project.
This Module is currently available.
4 AC-coupled mono input mixer
David Haillant's "Mixer 4" is a simple mixer with 4 AC-coupled mono input for Eurorack systems, in 6HP wide.
Each input has its own attenuation potentiometer. And the output gain is also defined by a dedicated potentiometer.
The components are all SMD, except for the connectors and the potentiometers.