Albert wrote:
snip
I must confess I haven't looked at halogen lights and don't know if
they are more efficient. They are certainly smaller and easier to
conceal. Additionally, they are dimmable, which might let us use a low
setting for sitting around watching tv and just crank up the dimmers
when we want to read or need higher light levels.

Maybe halogen lights are the answer?

....
They arn't much better than ordinary ones.
The tightness of the spots are the only good thing about them, and
that can rapidly become a problem if you try to light a room with them.
Are the fixtures you have returnable?
Anything that tries to use bulbs on their ends is going to be a problem.
You can flush mount some designs of 4' fixtures.

I'd be looking at nice dimmable ballasts and tubes, with well-chosen
phosphors, and go this way.

Have you thought of adding uplighters round the edge of the room, and
only using the cans for the middle, to fill in the dim spots?