Why not send an email direct to David Clarke, a headphone manufacturer in US and explain what you require. When I had issues with my noise cancelling headset they were great with advice. Their service agent at Bankstown is
Pacific Avionics Pty. Ltd. also excellent. They serviced and rectified the headset problems free of charge even though the headset was bought 2nd hand and was out of warranty.
Flightstore still has some Sennheiser headsets left and on special. Give em a call.
SENNHEISER S1 NOISEGARD [504211] - $899.00 : Flight Store -, Pilot Shop - 07 5536 8694