Ritteri, I hate to rain on YOUR parade dude, but IMO you have come on way too strong with your assertions. I'm thrilled that you feel so strongly about the merits of your chosen speakers, but...
Are you suggesting that the human ear is not sensitive enough to tell the differences between two same model Yamaha's? Why then, don't many players, and not just professional musicians, simply order a piano over the phone and call it a day? Why bother with test playing them in showrooms, and agonizing over the sometimes subtle, but obvious differences. Are you suggesting that the human ear is not sensitive enough to consistently tell apart a Yamaha electric from a real grand? Or from Dunlavy IV's? Musicians that you know were not able to do this? Professional musicians?!?! (And I don't mean to suggest, at all, that only musicians can do this) Just how much money are you willing to wager?
Email me privately if you would like to extend the challenge. Interesting, though, that you use Yamaha as a reference; of all the major piano brands, probably the least harmonically rich and complex.
Anyway, I agree with you that there are a few speaker systems can come pretty close to reproducing the sound of a real piano. But the impact, the resonance of the wood, the complexity of harmonics and difference tones that even the best recording equipment has trouble capturing? Close? Sure, but no cigar. To suggest otherwise also means that playback equipment and amplification has reached a level of perfection that, I think, most here would agree is simply not the case. Speakers are, by definition, at the mercy of what came before them. As good as it may all be, it's all far from perfect.
Now, about that challenge...
Seriously, happy listening, and don't let this hobby lose it's mistery and challenge. When it starts to happen, I asure you that you're just not digging deep enough. Reproduced sound will never be able to sound like the real thing. Close maybe, but as they say...
Support live music!!