I have an idea, however have not yet built it, so I can't say for shore that it works . I would like you all to take a look at it and tell me what you think. It's drawn up in this drawing for 3 inputs with 6 channels, but this can be scaled up or down. The circuit uses 6 normal relays and 2 latching relays. The user selects the input by pushing one of 3 momentary push buttons. Besides these parts the only other part in the circuit is 3 diodes, no other semiconductors are used. The simplicity of this circuit is worthy of Mr. Pass himself. Tell me what you think.