I did a (rather crude - breadboard) experiment of using an analog vs XOR freq doubler driving a flip flop. I did not see much difference between the $0.10 XOR doubler vs the $6 analog doubler. Two $0.10 2P4T PCB mount slide switches would replace the relays. The total parts cost for the device looks like less than $10 plus the PCB cost... which for 50 pieces of a 3x3" four layer board would be around $3 each.