I wonder if Hifiman could ever experiment with memory foam in their velour pads. Whatever they got in their velour pads is extremely firm, and it's starting to get to me on the comfort front. I like the fact that they're firm and that the pads won't deform over time, I'm a huge stickler for deformed pads, but I also don't want a pad to suffer on possible fit, seal and comfort issues if it's too firm.
I know AKG uses memory foam in a few models (including the new K702 Anniversary Edition.) Trouble with memory foam is the warmer it gets, the softer it gets. So the longer you wear them the more they change. It's both good and bad. Good because it forms to your face more. Bad because it changes the position of the driver over time, so you'd want it to be extra thick so the ear doesn't touch the driver housing more than is needed. Also it tends to store heat...even the open cell stuff.
Try to find some of the OLD HFM pads for comparison. Both the material of the velour, and the foam stuffing inside were substantially superior quality to the new ones. The new ones are made out of dollar store grade materials more or less, especially in contrast to the old ones. The trouble with the old ones was the horrible attachment system and the exposed hard glue on the inside of the cup. They were made horribly out of good materials. The new ones are made well out of horrible materials.
I didn't notice the original post that started this discussion. Are you going into the headphone accessories business?