Perhaps some basic GPIO abilities on the RPI. You could use them to reset/power rigs without the need of a smart plug if end users tie into the power switch or reset line on their mobos.
Do you have a link where I can read about it? Those seem to be 2 slightly different use cases which I would need to implement:
1) switch PSU off-on on rig "failure"
GPIO voltage = 3.3v -> PSU on
GPIO voltage = 0v -> PSU off
GPIO voltage = 3.3v -> PSU on
2) reset PSU on rig "failure"
GPIO burst 0v->3.3v->0