You'd have to mod the case and do some wiring, but since the ErgoDox is just a Teensy running QMK you could in principle hack it. I think all you would have to do is find an unused pin on the uC and then wire that pin to the foot pedal and recompile the firmware.
But the only real advantage to the ErgoDox over the Kinesis in my opinion is that it runs QMK: the key-wells are more ergonomic and the thumb cluster is better positioned because of the slight vertical height difference. And if you get a Stapelberg converter[1] PCB made, it doesn't look that bad to add.
But the only real advantage to the ErgoDox over the Kinesis in my opinion is that it runs QMK: the key-wells are more ergonomic and the thumb cluster is better positioned because of the slight vertical height difference. And if you get a Stapelberg converter[1] PCB made, it doesn't look that bad to add.
[1] https://michael.stapelberg.ch/posts/2013-03-21-kinesis_custo...