Thought I'd put a topic for Demo discs. I got 2 more of them in the mail today.
I have 4 recent ones, and I took some pics which I can send to Julien.

Toshiba high quality demo disc. No catalogue # on it at all or a date but disc marking are B10G00516 and back cover says "produce regional group Asia international sales & marketing department"

Hitachi Demo disc Japan Destination Groovin. Plain white jacket with corner sticker. Nothing else printed anywhere on the jacket. Disc label has minimal wording, but no date or cat # on it. Side b label has some Japanese printing? Disc marking says B20I01003

Sony Action Arena 3 demo disc 1992) cat HLV-9053
Side (A) Circus Fantasy
Side (B) Irodori (Hokkaido, Kita Alps, Kyoto, tokyo)

Sony Evolution Kirara Basso demo disc 1996 cat HLV-9121
Side (a) 4:3 edition
Side (B) 16:9 edition for wide screen tv

I thought side B might be squeeze, but looks like it is not. On full view I stil get bars top and bottom and it doesn't fill the whole screen, so it has to be widescreen letterboxed. Unless your suppose to use zoom?

I've got a very early Digital Audio demo disc, but just the disc, no jacket. I also picked up a showroom promo disc, but I don't think that's quite the same thing.

That Quasar disc sounds interesting. What's the picture quality like on it?

I still really want to get my hands on Leonard Nimoy Demonstrates the Magnavision Videodisc Player (1981) [07-562].

I'd say it's pretty good, although not quite as good as the best scenery discs ; it was meant to show off a TV, after all. On the other hand, you do have to live with the distracting caption/logos.

Most of my demo discs have corner logos too. Only my 8" Aurex DSP flashes a logo at the start, and nothing on the actual video clips.

I looked for that Nimoy disc for years. Finally tracked it down in pristine condition complete with the original insert. Put it in the player and... laser rot.
Others I have:
Laser Optics II: The Future of Home Entertainment (1989) [PA-89-01]
MGM/UA Home Video Laser Disc Sampler (1993) [ML104779]
MGM/UA Home Video Laserdisc Sampler [ML102880]
Panasonic TV The One Demonstration Disc (1991) [PA91-01P]
Toshiba Cinema Series (1993) [---]

I have an extra copy of the Toshiba Cinema Series disc. It is in very rough shape from actual showroom usage, but still plays perfect. I'd be happy to trade it for a demo disc that I don't already have.