A pianist
Interesting! Sounds like the right time for that kind of thing. Although it has loads of things that don't quite work, it does have the closest thing to the right 'spirit' that I can think of in a recording. I hate many of the weird hesitations and suddent dynamic drops mid-phrase, but I have never heard another performance in which the central climax comes off so well. The playing within that section strikes me as somewhat akin to just how Nyiregyhazi might have sounded in his prime years (although I wonder whether the Nyiregyhazi sound would have been even more terrifying still).
What I would love to hear would be the Liszt sonatas that were recorded in concert in the 40s. Apparently they are cut slightly (I can't imagine how you could possibly cut the piece!), but I would imagine that it would be an interesting balance between the styles of the two commercial recordings. I'm also intrigued by the thought of the 40s Ver la Flammes. That could really be something! It's a shame they released a 70s recital for that 'rediscovered' series, rather than something that would really be of interest.