There's none that I'm aware of. Doing some digging around the internet on the subject, the impression I'm getting is that D3 has no built-in support for it, and isn't likely to get any anytime soon outside of official avenues, and seeing the game hasn't had an official update since 2001, well... 

From the comments I'm seeing, some from which I know are players that know way more about D3's inner workings than I do, it would appear such a mod can't be done without access to D3's source code, which to date hasn't been released to the public (and there's no guarantees that it will be anytime soon).

Max you can apparently do is 1600x1200, which when the game released, was pretty impressive for '99. I'm seeing hints that there might be various ways to milk 4K out of D3 with the use of third-party apps, but there is still apparently a loss of FOV at the same time, so I don't know if it'd be worth it.

I might be able to find more info with more digging than I can spare the time for at the moment, but it's certainly looking like I wouldn't hold my breath on it. Sorry. 

@vanguard... I could not have said it better. After school I would rush home and play my favorite level "Subway Dancer". I can even remember some of the twists and turns and my dad not understanding why I didn't throw up.

I guess I'm still around once in a while. I even played some Descent 1 recently.

I remember Stickman! I might still have an old copy of one of the "demos" you made of it too, on one of my older computers...I'd have to go digging to find it, though, and no idea if it'd still run, so...

Welcomes!