The whole thing about speakers above the ears might be a little mis-leading. I think that its more to fire over blocking furniture, and in your case, people! In-ceilings are typically recommended as a last resort, if I read things correctly, but I think in your case that could be an excellent solution. For it will let you put them in ideal positions, speaking in terms of 2-D. The ceiling mount will present zero issues as far as blocking audio from the front row. (How much higher is the back row?).
I would consider something like that, but I already have all of my surrounds speakers, and they are very large for bookshelves. I put a pair basically straddling the two rows (a somewhat common compromise I found with others as well), but its less than ideal surround for the back row. Ceiling mounting should take that issue out of the equation. My rear speakers are also on stands behind the back row, and the height of the back row definitely is blocking the sound, but its better than nothing, IMO.