why be sceptical?
who's to say what is possible, the human mind is an amazing thing. Nature is an amazing thing.......this basing everything down to science and thinking everything has some kind of scientific explanation, or that it is not possible to master your mind in such a way that you can perform exceptional feats is a very closed minded view in my opinion.
I mean where does science come from? There is too much unexplained for me to shut off the possibility that humans aren't capable of these kind of things. One such example I like is....what is electricity? I mean we all know how it is generated etc, but how the fuck (excuse language) do we manage to make it do all these amazing things like tv and computers and lights and everything? I mean there is no real reason behind it is there? I don't think it is possible to really explain how some wind, or some moving water can make me be able to type a message on here and be seen by everyone else from anywhere is there? It all comes from nature, or as I think I have read Tohei put it, the power of the universal. What's to say that we can't harness this power ourself and skip the intermediates, like the windmills etc huh? Being sceptical and denying the fact that it is possible, is just denying yourself the chance to maybe someday experience it.
So in my opinion, yes it is a very real chance that o'sensei was able to perform such amazing things, but if you are able to, what is the need to demonstrate other than to prove something to yourself, and if you can already, why do you need to prove it to yourself?
Anyways I hope you are able to understand what I am trying to say in my rather long winded idea, and please by all means, keep your minds open