Wow just finished reading this epic thread. I won't commit to too much but the gears are turning in my head and ideas are leaking so there may be some fun new TP's in the world whenever I get a chance to actually try out what I'm thinking. I have an old broken pair of Audio-technica A-5's that I might cannibalize the headband from..hmmm.
BTW I imagine someone would have mentioned it already but anybody know if you can buy just the drivers somewhere? It seems like such a waste to buy the whole headphone just for the driver...
Oh, and anybody ever try and make an angled baffle like in the audio-technicas? I have some a700's and I was thinking the angled driver could be fun, but it might make the baffle too big since there isn't much room in the cup, not to mention it might change the damping characteristics too much.