There were a few around the mid 00s - namely the HCT DH-720G, the Guillemot Thrustmaster T510 and the Creative HQ-2300D. Iirc, all three were bundles (decoder/headphone amp unit plus headphone), and the HCT and the Thrustmater looked pretty much the same, but the HCT would additionally decode DTS, while the Thrustmaster would only sport Dolby ProLogic II and Dolby Digital (AC3) decoding.
I'd suggest to look for the Creative, though, 'cause that would sport not only (also) ProLogic II, Dolby Digital and DTS decoding, but also two separate 1/8 "/3.5 mm input jacks for analogue stereo/surround and optical SPDIF (rather than a combined one) - and its output jack was directly integrated into the decoder/headphone amp unit rather than at the end of a short, captive output cable.
Greetings from Munich!
Manfred / lini