"Personally I am hard pushed to explain why some of the more revered headsets are as expensive as they are - it is certainly NOT a function of the components, since there are many better performing headsets used in the broadcast industry for example that cost less.
One reason for the cost may be FAA TSO certification, though not all headsets used in aviation are certified. Certainly certification adds cost. "
Thats is the same questions I have been asking myself.
Did some google work and found others who actually made some headsets.
Looks pretty promising and will probably try it out later in the future.
Can't wait to use my Koss Porta Pro in the flight deck, nice and neat!
Homemade Aviation Headset
Sorry for the google cache, the original website seems to be down...
Take care!