This is kindof backwards from what we usually do.
A friend has a house that was "prewired for sound." What the contractor did was run a bunch of speaker wire from the corner of the living room to the ceilings of other rooms, with no wall drops for volume controls.
Because of cost and architectural limitations, running new wire is not an option. Trying to extend speaker runs down the wall for a volume control is not an option. It's possible, but, I say again, not an option.
I've been looking at various speaker distribution panels, which is close to what this project needs. What I'd really like is a pretty distribution panel with 4 or 6 volume knobs on the front, adjusting the volume out to each speaker group. I figure I could build such a beast easy enough, with a stack of volume controls and an impedance matching speaker distro. But I'd rather find something off-the-shelf, and be done with this project quickly. Since I can't get local control, I'd like to at least get individual control.
Any ideas?