I would modify Greg's description to mention 2 different points on the input slope. For instance, with a 10V supply, it might take >=6V to turn the gate on, but <=4V to turn it off. 2, 10K resistors could be placed in series across the supply to place 5V on the input. Momentary switches across those resistors, (probably with their own series resistors to prevent shorting out the PS), would be able to switch the output back and forth.
I would also agree with you both on relays if our OP is using line voltages and large gaps. I picture those photocell circuits that ring the bell when you walk into stores. 2 of those and 2 relays or 1 latching relay, would be all that's needed for what I think he's trying to do. But for small gaps and logic level supplies, I picture a flip flop with preset and clear driving an opto, SSR, or relay via a driver ckt.
Joe
