Does anyone know from what show these video is? As far as I know, only Game Music Festival '90, S.S.T. Band Live and S.S.T. Band Live History was released.

http://www.youtube.com/watch?v=bfb8rNwtSg8

I think I know where it might be from
(since it's not on the sources you already mentioned)

Power Drift CD-V format release from Pony Canyon/Scitron (1998)
Catalog Number: E20H-1003

Contains 1 video track, and 3 audio tracks
Front Scan
Rear Scan

I purchased this a few years ago, but since it was a CD-V format my computer's dvd-rom drive only picked up the audio segments and not the video segment.
Being I couldn't get the video part to play, this is an unverified guess, but it seems like a strong possibility.

Hey, Carl, this album seems very rare! I never saw it before and isn't catalogued in VGMdb.

By the way, in Nico Nico Douga I found a extended version of  "Magical Sound Shower" with 11 minutes (GMF '90 and '91 versions has only 4 and 5 minutes). I think it's from the same show, but was released in another CD... Perhaps a similar album of OutRun...
http://www.nicovideo.jp/watch/sm482100

If you aren't registered, here goes the video:

http://www.mediafire.com/download.php?mmo0oyzqyym
http://www.mediafire.com/download.php?yhmxmmimyjo