Im thinking aout implementing a similar resistor ladder, albeit with Transistor Arrays. Not sure if a suitable part exists... (Im a noob). I have found many transistor arrays with 8 common collector darlington pairs, but Im wondering if an array with 8 transistors with no common collector exists. I have found one with 3, but that doesnt help too much...
How about optocouplers or MOSFET solid state relays?