Hi, I'm in the market for some acoustic guitarists similar to Uaral.

What genre does this style of playing fall under? I imagine it's classical or folk; both even...

Here are some examples; 'Lamentos...' and 'Surrendered to the Decadence II'.

I guess you could say I'm looking for some doom-esque acoustic guitarists; slow and beautiful but full of sorrow.

Any help would be much appreciated!

You'll like Empyrium, they use clean vocals though, but they're pretty much in the same vein.

And I'd think it falls in folk/dark.

Empyrium's last two albums, Vali's Forlatt demo and October Falls (before this last album which is apparently metal. I've not heard it yet.) are pretty much in the exact same vein of what you're asking for. You may also want to check out Nest which sounds pretty similar to that.

Uaral are quite possibly the most hilarious band in metal.