I just did a church installation using the AR "Edge" speakers, and they were surprisingly good-sounding and well built. They come with a very elegant wall/ceiling swivel mount and are available in a nice off-white. they are $200 a pair at Crutchfield (website only, not in the printed catalog.)
Three pairs of these would be $600. You could get the AR or Sony 12" powered sub for $200-$250, and still have enough left for a reasonable center.
You'll probably have to live with black for the sub, but presumably that isn't a big WRF issue, since you can hide it under a table or something. I don't know about a white center speaker, but if your wife could live with an attactive natrural finish like rosewood or something, you should have some decent options.
Another possibility would be the Sony SA-VE815ED, which is a 5.1 system that has gotten some nice reviews. It has small, oval satellites on swivel mounts and (only) comes in a sort of silver/white that matches the Wega TVs. Even the sub is this color. It is $999 at Crutchfield and others. They sell extra satellites at $150 each, so you could have 7.1 for $1,300.