Thanks!
I have tried the top pair inverted, it sounded excellent like that, however with both pairs right side up it makes the sound stage seem larger than life - more vertical dispersion across the whole spectrum. The ribbon tweets do an excellent job of not spraying sound vertically, so it's not reflecting off the ceiling or anything.
With that big TV in the middle it sounds just right on movie soundtracks so that's how I leave it for now - when I get the time I thought about making stands to put them 24" high, and side by side, unless I get a bigger living room, in which case I think 7.1 will be in order.
The picture isn't deceiving, my living room is 14' wide by 22' long, one pair of these with good power was more than enough for this size room, but hey - three pairs is better than one, right?

I plan on adding a second subwoofer in the near future, or maybe getting a bigger one.
I have the front two pairs, and then one rear pair wired as mains for stereo music. I turn the rear ones off to watch movies, and they have a set of Bose 201's on top of them for actual surround duties. They spend more time running music - according to the meters on the carvers, about one watt for general listening, and about 80 when I turn it up.
If anyone knows anyone with some S-1010's for sale, I might be interested to try them!