Hi Rob
I'm not sure if these converters support high bit rates, personally I'm quite happy with 16 bit CD standard.
But then I'm probably a deaf old bugger by now.
The one shown in that ebay listing only supports 16 bits up to 48KHz. Mine is probably the same.
So if you are into more than that I don't think I can help - but my own humble opinion is that there is far more going on here than bit rates etc and that the main thing that matters is the quality of the audio engineering - and the built-in USB converters in a lot of DACs simply aren't very good.
Happy to loan as offered if you are still interested.
No, it's not for sale, I want it back once you've had a try! I do use it occasionally.
btw - I think once you get to 5 posts you can start using the forum's Private Message system.