I'm looking into some glass braided wire for my temperature sensors. This site shows prices for their thermocouple wire in the 1-99 ft range, so I'm going to see if they sell to the public. The thermocouple wire is rated to 800-1000 F temp, but the gauge is only 20 - 24, so it's not big enough for 110V pumps.
Plastic Process Equipment
They do have HI-TEMPERATURE WIRE in higher gauges rated for 400-800 F temps.