Hi Brian: I too remember that show. There are a number of companies who make in-wall speakers. A NET search should find multiple vendors.
A word of caution, though. I went through considerable research about 14 months ago for small or inconspicuous in-wall speakers for our newly remodeled formal living room. My first thoughts were directed towards the tiny Bose cubes or in-wall units. During my research, I discovered many things I didn't know; one of them was that although they are inconspicuous, in-wall speakers are very limited in the sonic capabilities, with their only real value of providing soft back-ground music at low volumes. For sound quality, they are usually rated very poorly by those who rate speakers for a living...almost as poorly as Bose speakers.
FWIW, I wound up going with a pair of NHT Superone satellites, mounted high in the corners of our living room (relatively inconspicuous) and a single non-directional Hsu subwoofer that looks all the world like a corner table.........but what sound!!!