Thanks everyone for your replies, and thanks to Jim for his nice welcome. You've given me a lot to think about, and I already feel a sense of adventure about this.
To answer Jim's question, the only reason for the 3 to 4 feel above the floor requirement is to get the axis of the drivers approximately at ear level (when I lie in bed my head is about 34-35 inches above the floor). There is nothing currently on the floor at the proposed speaker locations, so speakers could be placed on the floor there. But unless they are pretty tall, or slanted upward, or on stands, they would be firing below ear level at a big, bulky bed.
Actually, on the 12 foot wall opposite the bed the speakers could be placed anywhere from directly in the corners to 2-3 feet inward, so the distance between speakers could be anything from 6 to 12 feet. In my original post, I thought 6 feet was best. Again, I see the problem is getting the driver axis at ear level, but maybe that is not necessary. Perhaps small floor-standing horns placed near the corners and slanted slightly upward would be a solution.
Anyway, you've got me thinking about ways to fit SD speakers in this room, and pointed me toward some speakers to consider. Any further thoughts would be welcome. Thanks for the help.
pjg66