Just a heads-up for anyone interested in my Quadra 7100b hack:
(1) In response to a query from eeun, I've cut down the Quadra 700's original speaker bracket and installed it, to help stabilize the 7100 motherboard:
(2) I went ahead and sprayed on a third can of Molecubond/Colorbond. Looks much better; now the whole unit looks as uniform in color as the final shots of the front of the unit in my image gallery and on the hack page.
(3) For those wondering, the keyboard doesn't match the color of the CPU; it's not just the photograph, they really are different colors. Unfortunately the only dark color of Molecubond/Colorbond available to me locally was black.