Quote:
If you want a software solution, it wouldn't be too hard to setup a linux box with a sound card. Here are a couple I've found for a project I'm working on, I haven't gotten to the point of the visualization pieces yet, I've only slightly researched it. I'll be trying Synaesthesia first I think, as it's one of the only ones with half decent documentation.
I have moodbar setup already, and I have a nice ruby script which will generate png images to the filesystem... if your interested let me know.

Synaesthesia
Fische
Moodbar

If small is 'in car' then maybe this is not on - but 'in house' then I'd guess a second-hand laptop butchered to fold back on itself like a tablet PC would be the cheapest way to do this.

Hmm, how would you sync displays between multiple devices?

A beowulf cluster... no, stop that

Actually, I quite fancy this idea... mount a laptop screen in a wooden frame and recess into a drywall for a remote picture frame that also does music and video...

Yes....