OK, another pair of unknown extender cards:
http://ana-3.lcs.mit.edu/~jnc/tech/jpg/tmp/LargeExtender.jpg
If anyone has a use for one or both, FTGH.
They are 17"x10", and the support arms (nice touch) are about 3" long.
No identifying marks that I can perceive, alas. The power leads are titled
"+5", "+12 Handler", +12 Return", "+12 Scan",
"+15", "+- 15 Return", "-15".
Noel