Transparent is a term that refers to optics. Like "as the artist intended" it is a nonsense term IMO. Since for the Nyquist Shannon sampling theorem to work it would require an infinite bit rate, any ADC or DAC is going to be a compromise to some degree. Then that doesn't even get into the electrical considerations of the design which are another whole level of complexity and potential issues, but it is why you can't have a DAC without both pre- and post-ringing on impulse signals that isn't non-oversampling and NOS DACs introduce different distortion issues.
Maybe the closest would be a non-oversampling DAC fed high-res "studio master" recordings? But then that doesn't eliminate any digital editing done to the music post-recording. It rather reminds me of the $70,000 turntable rig that is so good that 95% of records are too poorly made or recorded to be enjoyable listening with it or listening only to binaural recordings when listening with headphones. You'd be limited to some direct-to-digital recordings with no post-processing. Ouch.
The thing is, we are here seeking enjoyment of music. For some people, having equipment in shiny, artistically designed boxes is important to help them enjoy listening. Likewise, for some, knowing the DAC measures well* helps them with their ability to enjoy owning it.
There are plenty of DACs from about $1000 and up that have "excellent" measurements. Still, they all sound different, often very subtly, to the point that I've seen quite a few recent reviews of $8000-10,000 DACs where the reviewer admitted there was little to nothing in it between them. So I reckon if you have bucket-loads of money, I'd just get an MSB, Esoteric or dCS stack and be done with it.
*Whatever that actually means, as actual music isn't the same as sweeps and tones played into a measurement box.
