Well, the corresponding debate over on the "guitar forum" *ahem*, came to a similar conclusion - and actually recreating the sound, feel, and everything else is pretty much impossible.
Which got us onto the characteristic mid-range snarl. The conclusion was EQ'ing and preamp, but a certain pickup winder said he could do some of that with magnet, slug, wire and wind choice. The challenge was on - he's building it - I'll fit it in one of my 51P's and see how it sounds