Available as an assembled Module and as a DIY project.
This Module is currently available.
Relay based switch.
Simple relay based bi-directional, single pole, double throw, momentary switch. The three switch terminals are wired to jack sockets on the panel. The switch can be actuated by the panel push button or externally controlled.
The relay is plugged in to a socket through the panel, so can be easily swapped out. Many relays are compatible with the module, each with it's own sonic character and switching characteristics. All these relays are capable of switching at audio rate frequencies. The relay is backlit with a real miniature bulb.
https://www.tindie.com/products/hackmodular/1606-electro-magnetic-switch/
Hack Modular 1606 Electro-Magnetic