In case you are not aware, there is a company in Germany, selling used piano's, with quite a sizeable amount of sound clips from the piano's they sell. Not all piano's have been sampled this way, but they still provide a good glimpse into the characteristics of sounds from piano's of different sizes (both grands and uprights) and brands. The playing itself is not perfect, but must still have been done by a pro.
Bear in mind that there is a clear bias towards German brands.
EDIT: And while I'm at it, I should also point to the Youtube site of a Dutch piano retailer with lots of video's portraying lots of different piano's: