Not sure what the NEC makes of these, but in Europe there are cables under the brand names Tersil, Efglas, and Intemp which might be on track for what you are after. At least two of them are intended for aerospace applications. They are carried by most of the major component distributors over here.
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If we learn from our mistakes,
I'm getting a great education!
You didn't say what size you want, but do a search on PTFE (teflon) insulated wire. There are several UL listed mfgrs, but usually limited to control wire.
"Venditori de oleum-vipera non vigere excordis populi"
What is usually available around here is 180 degree Celsius rated wire. This is what is used for motor leads when rewinding motors because motor shops almost always use 180 degree Celsius magnet sire and varnish.
I have installed this in industrial machines that have strip heaters and radiant heaters. The insulation has glass fiber cloth over Teflon insulation as far as I can tell.
