fuel pipe heating
In oil refineries it is common practice to pump large amounts of heavy lube and fuel oil for distances of up to a mile.In order to keep the oil from cooling and becoming too viscous to pump "trace heating" is used. This consists of a small diameter pipe wrapped round the pipeline which is then heavily insulated. Low pressure steam is passed through the tracepipe.By substituting steam for electrical resistive heating tape and insulating the fuel pipe is it not possible to warm the fuel before it gets near to the engine? This would be a more elegant solution than piping bleed air around the wing. Just a thought.
This is exactly what is used in the cargo bays to stop water from freezing inside the service pipes (resistive heater tapes that is). I'd imagine it'd take a load of research and money thrown at it before they'd ever certify electrical heater tapes on a fuel system pipe.