I have a Mears M600S Line Voltage Electric Heat thermostat. It has two individual circuits in it. One circuit for each side of the room. I'm having a great deal of difficulty finding a replacement. Does anyone know where I might find one or an equivalent that has two separate circuits each rated at 240V/22A?

If you haven't already, try grainger.com or furnaceparts.com. Re-post this in the heating & air conditioning forum for better response.