In all the cases I've heard about, including my own, the vapor lock occurs when the bike has been parked for 10-- 15 mins. Heat builds up as the pump and inlet sits right above the cylinder when on side stand. 20 mins later its fine again. It isn't a problem when the bike is moving, and you should have air flow over it when running. Locating pump inside tank provided a cool liquid for the pump to stay cool in.
All you need to do is shield the inlet line to the pump and MAYBE shield the pump itself. I shielded the line only and have not had the problem reoccur. I'm convinced the vapor lock is in the line before the pump, not in the pump itself. If there is vapor in the pump but fluid at the intake, pump will still pump fluid. If inlet to pump is vapor then pump will not overcome the suction.
In terms of volume, you will get vapor in the fuel line before enough heat builds in the pump to vaporize the fuel there.
It's a $20 fix and takes half an hour. No need to over engineer the problem.
As for heat escaping... not a problem as it never builds up to begin with.
cheers,
Rj