my room is 12x18 with 8 ft ceilings but one of the sides is completely opended to the rest of the house which is about 50 ft long. i am using set of jbl northridge series speakers for ht. they come with wall mount hardware. they are amazing for the money.
if you are really considering the grand pianos, look for the original the ones that came out about 1995. they are much better then the current home version that came out around 2000. the original was much more refined and neutral. take a look at this review of the concertino home. the review compared it to the original, http://www.videohifi.com/Concertino_eng.htm. sf wanted to optimize the speakers for ht during the boom. that is probably why they named it the home series. they changed the drivers and made the speakers more efficient but sacrifaced a lot of the sf magic.
good luck.