Well, I have nothing nearly as fancy as those cool wood phones, but...
These are the CUI piezo elements that I used with my one tube radio for the ARF homebrew contest last summer. They were tinny, but the most sensitive things that I had available. As you can see I put them on a cheap set of Walkman style headphones.
Overall they were not very satisfactory.
Last night, after being re-inspired by this discussion, I finally got around to taking them apart and installing the elements into a set of hearing protectors.
Since these elements have pins sticking out the back, I just pushed them through the foam and then through a piece of perf board (sandwiching the foam in between). Then soldered everything together. That saved the trouble of having to glue the elements to the foam.
Then I drilled a few holes in the headband, and threaded the connecting wire through to hold it in place.
Not surprisingly, this is a vast improvement over the previous Walkman style assembly. Mounted this way, there is considerably more volume, and audio fidelity is much better. Obviously, they are nowhere near hifi quality, but I was surprised at how much the bass response has improved. This is definitely a useable set of phones now.