i just shot this video today and uploaded it unedited to youtube.
the barrel frame is the 10 key cut from a model M terminal - a leftover from my terminal SSK hack.
the hammer/springs are model F/model M, arranged checkerboard.
the top two rows have Oral-B Superfloss loaded down the springs.
the two right-most columns have 1/16" (1.5mm) neoprene sandwiched between the barrel frame and the back plate.
http://youtu.be/MMQ82Rnl7JAi suspect that YouTube normalizes volume. in the raw video, the sound difference is much more pronounced.
the 4 top right keys with floss and neoprene are the quietest slightly edging out the neoprene only. if you don't bottom out then these make very little noise at all. if you do bottom out, they are about equal to Cherry browns.
the floss suppresses the spring/barrel noise and will work for model F and model M equally well. the neoprene suppressed the bottom-out noise but is probably not practical for a model F switch keyboard. it would work with a model M switch keyboard but some experimentation might be needed to see where is the best spot for the pad - between bottom membrane and back plate, or between barrel frame and top membrane in place of the latex rubber pad. longer bolts (+1mm) might also be required.
i got the neoprene from McMaster-Carr
part# 8647K102, 1/16" extra soft neoprene, $3.80 for 1' (by 42" wide).
