There'll be a white LED in every mirror corner intersection, and certain
2x2
panels will slide out of the wall as file drawers etc.

One of the few art pieces of Andy Warhol I like is like this. He had
several mylar neutral buoyancy ballons as well.

Perhaps you can make frames of .75" square stock and "upholster" them
with mylar. They would be *much* lighter than the glass, although less
durable.
You would be able to run the LED wiring in the space behind the frame,
or perhaps put the lights behind the mylar if it has sufficient
transparency.

I was a mirror room exhibit at Albright Knox art museum in buffalo, but it
was dark inside. I want to explore the psychological effects of working in
a small room or mirrors - can you trick yourself into believing it's a
larger space, etc... and how many LEDs will be enough to light the place...

Great links. $1700 for 100 of them is great. I was going to avoid acrylic,
but maybe it's not that important as long as the underlying surface is flat
and smooth...

Thanks!
-JB