DEC used a lot of these on it's systems.
Their external TK50 drive:
http://research.microsoft.com/~gbell/Digital/timeline/1984-6.htm
Their BA123 style enclosure--the nameplates you see next to the
power switches are separate pieces of plastic which snap into the
plastic of the case, if helps at all:
http://research.microsoft.com/~gbell/Digital/timeline/1985-2.htm
http://research.microsoft.com/~gbell/Digital/timeline/1985-4.htm
Their VAXstation 2000:
http://research.microsoft.com/~gbell/Digital/timeline/1987-2.htm
The base of their VT-240 terminal is another example, but I can't find
any clear pictures of it:
http://vt100.net/docs/tp83/full0303.jpg
http://www.montagar.com/~patj/dec/ware/GRA_SOF_REF_GD_VT240_241_1984.JPG
The one example I have on hand is on my VAXserver 4000-300, though
mine's manufacture date is Feb 20, 1991. I can find confirmation, but
I believe these were first being built a year or two before that time.
http://www.jarai.org/temp/0629_001-sm.jpg
http://www.jarai.org/temp/0629_002-sm.jpg
http://www.jarai.org/temp/0629_002-sm.jpg
There's also the VAXstation 3100 and DECstation 3100 series of
computers. I couldn't find a clear picture, but here's a diagram
for the back of the case used by those models:
http://www.whiteice.com/~williamwebb/Chap2/DOC-2-6.html
-brian.