[bjgregory]

Well, based on the P-38K which would have probably been the airframe used with modification for the Merlins, it would be capable of speeds over 500mph, much like I suspect the P-51J would have been capable of.

Yeah, it would have been interesting, that's for sure. The Merlin 130/131 versions with the reduced forward area weren't available until after the war, I imagine that was a fairly big reason that the Merlin was never considered for the 38 in time.

On the note of conspiracies, the YB-35/YB-49 programs weren't accepted by the government supposedly because Northrop wouldn't merge with another company.

Weeelll, it says that on Wikipedia, so it may or may not be true. The project *was* dogged by technical failure as well.