digital front end to rival best vinyl?

Doesn't exist. What you are comparing is analogue to digital. Stop chasing the 'analogue' sound, just live with digital. Remember it is the source that should be compared. I've listened to some blu-ray audio mastered from the analogue tapes on some titles I have in analogue, reel tapes, and while close, still can tell there is a difference. Analogue still has the edge. As more and more analogue is remastered to blu-ray, that may change. Since there is a lot of new vinyl that can be compared to the cd equal, you must decide. Part of the problem is that the vinyl is being cut from a digital source, often with all the EQ and other 'enhancements' added, so you never really hear the analogue sound as source. There are some titles that do go directly from the analogue tape masters to vinyl with little 'processing'. I think the Beatles project missed an opportunity to not issue a few blu-rays.

What works for me? Analogue, vinyl and tape, with tubes.

To specifically address your issue, I suggest you pay close attention to what Tvad and Buconero117 said in their posts.
Vinyl and digital will, probably, never sound the same.
And one person's silk purse is, always, going to be another person's sow's ear.
As far as getting the best sound you can from digital sources, I can only suggest what has worked for me.
First, optical drives seem to all suck. Always play music right off your hard drive--even if that means loading the CD's content, first, off of it on to your hard drive before playing it.
Secondly, to know if you have the right computer set-up, it will be one where the volume controls of your computer don't work--but the player's (like Foobar) does.
Thirdly, I suggest using a sepearte component solely for converting the USB signal to S/pdif before sending it to your DAC.
And this component should have a huge power supply. Don't use what comes with the converter, supplant it with a big computer power supply (I use an HP 6203B) set to match the AC voltage needs of your converter--effectively matching its "wall wart".
Fourthly, the output impedance of the converter and input impedance of the DAC seem to effect things. So, you'll need to try different digital cables to get a good match.
Fifthly, there seems to be a "sweet spot" in your music player's output level. Find it (by ear). Set it. Forget it. And just use your preamp's volume pot.
And, in conclusion, as far as what DAC to use, IF you're looking to get that "vinyl sound" out of it, use one with a tubed output.
Disclaimer: I have no idea why any of the above matters. I discovered it through lots of trial and lots of error.
I could go on. But, I just finished my second martini and can no longer type.

Nope.

a few months ago i did add a server, with 176/24 and 192/24 hirez files. they sound wonderful. much better than redbook.

but i likley prefer the best SACD's to the hirez PCM i've yet heard, let alone 'the best vinyl'.....which i have in my system. then there is 'the best reel to reel master tape, which beats the best vinyl.

i will qualify this by saying that my musical and sonic sensibilities highly value those aspects of music reproduction which are preserved by analog recording. i think live music sounds more like analog than digital (especially PCM). so if one values the added leading edge energy of PCM and don't have a problem with the reduced space and body with PCM.....then possibly digital could rival the best vinyl.

this is a subjective question; and i have friends i respect who prefer a digital hirez master to a RTR tape master. my ears tell me something different. and i know how the best of analog recordings make me feel compared to the best digital.

i do know what happens when i have friends over and we switch from listening to anything digital to Lps or RTR tape. we rarely if ever return to digital.

btw; i love digital and have top level digital gear.

You will have to do a lot of research to find a hard drive based system that works for you.

Here is a company offering hard drive front ends: sonore.us

I have not heard these products so I'm not recommending them, but it may be a place to start your search.

The best digital front end I have heard is the new Naim HDX. I felt it even outperformed the dCs Scarlatti by a significant margin. It is still not as good as a good vinyl front end (what is?) but it is awfully close. I plan to get one once the 2nd generation units come out.