There may be strip heaters designed for wing de-icing with those dimensions and controls.
To make it would be similar. Minco and otehr strip heater manufacturers make various sized strip heaters, although, maybe not that long. You might need to buy a few short ones and glue them to a strip of aluminum. They should also be able to supply you with a controller that would have inputs for a thermistor or other temperature input. TTFN