AA's book, "The Print" mentions that he had used an "Air Force printer" which contained 12 lamps, each with its own switch. I could not find any reference to such a thing on the net.
That must be the one. Funny that the net does not have anything about this.
Addendum: the full text of "Print" by Ansel Adams is available at http://archive.org/stream/The_Print/The_Print_djvu.txt
Here is the relevant section from the book:
"Contact-printing light boxes have few advantages and one major
disadvantage in that the negative cannot be seen while printing.
However, for printing large quantities I have used an early "Air
Force" printer, which contained twelve frosted lamps, each with its
own off-on switch. It is thus possible to control the distribution of
light during the printing exposure, to broadly compensate for uneven
negative densities; turning off the central lights, for example, will
increase the relative exposure of the borders and edges of the image.
Actual dodging and burning, however, are quite difficult to accom-
plish with such a printer, since they require the use of translucent
masks, cut to the appropriate shape, inserted below the negative.
The printing-frame principle remains, for me, simpler and more