Speakers that do pianos really well

I recently had the good fortune to listen to a half a dozen pretty well-regarded speakers back-to-back. For these kind of sessions I like using piano recordings - either solo or jazz trio - as a measure because, to my ear at least, it seems that speakers that can reproduce piano really well seem to be pretty well sorted on everything else. The surprising thing was how many of these speakers did NOT do piano well. Of the group there were only two - Vandersteen and Verity - that I thought really captured the big chords, shadings, timbres, and reverberations cleanly and naturally. The rest - and I'm not going to call them out by name - offered a mixed bag of over-brightness, distortion, and general unnaturalness. I was very surprised by the results as I expected better from some of these speakers based on their reviews and reputations. So my question is, Does anyone else use the piano as a litmus test, and what speakers do people use that they think do pianos really well? Regards.
Piano is a great litmus test of speakers. Done right, you should feel the power and weight of the bass registers, but with clarity and detail. I suggest the Santiago Rodriguez performances of Rachmaninov (try Elan #CD42412). Check out track #2. On the sustained bass notes, you can hear the sympathetic waves of string vibrations roll up and down. This is a great test of bass realism for the whole system. The first time I heard this cut, I found myself holding my breath at the end. Speakrs were/are Von Schweikert VR6, VR5-Anniversary, and VR100XS.
The biggest issue that I have in using piano to judge a loudspeaker is the enormous variety in tonality between different pianos. It's not just grand vs upright, but various sizes, manufacturer tonality variations, and even the age of the hammer pads. I'm never sure what the particular piano on a particular recording is supposed to sound like. Okay, really bad is really bad, but maybe that clangy sound isn't the speaker, it's just a small upright with worn hammer pads.

Even if I really know a recording and am doing a controlled A/B, it's hard for me to really feel comfortable making a judgement on a speaker's ability to "do" piano properly. Shy of that type of comparison, I find voice much more useful than piano for judging a speaker's tonal neutrality. But, that's just me and YMMV.

Interesting point Martykl makes...all piano recordings sound a little different (some a LOT different) and that is where the mojo lives...i.e. being able to clearly and instantly hear those differences. I think a good sub really makes pianos come alive as an entire piano is making sound beyond and in addition to the notes being played...a piano is a large living thing with sympathetic vibration going on all over it and, if you're hifi's working properly, all over you.