I've listened to the Duntech Sovereign quite a few times in a mastering studio with the finest original recordings. Extremely detailed, which is why they are being used for mastering.
Dunlavy may be out of business but Duntech is not, so if you have the ching you can purchase these brand new.
http://duntech.com/products/sovereign.html
If the link does not work (got a weird warning from A'gon) then just Google Duntech Sovereign, they are in Australia.
Regards,
barts