For clarification, I already have a current measuring system, so I would rather not design one from scratch if it isn't necessary. I am specifically asking about the identification of multiplexer transistor architectures (if any) that are capable of switching ground to a no load, high Z or floating condition. (like a mechanical switch or relay but much faster and more scalable) Normally, low side switching with a low Rds On would be the job of an N-Channel Mosfet except they generally won't turn on with an unloaded drain pin. (to my knowledge) Are there any solid state switching topologies that are capable of this?