Flawless production, great lead work on guitar(solo's). Would prefer vocals that are audible for the most part, harsh and spoken vocals are welcome as well. I'm looking for something along the lines of Keep of Kalessin's - Kolossus!

Try last Abigor, Enthroned, Celebratum, Naglfar, Cirith Gorgor...

Immortal

Lord Belial
Khold (maybe)

Yeah, I would say Lord Belial as well, specifically the "Scythe of Death" EP, it is my favorite release by them, and it features very good production, and definitely the some of the best solos the band has done.

Try Crystalium's last album. It's got some really nice solos, and the production is very good.

A band I worship...

Aaskereia!
Their only album "Mit Raben und Wolfen" is amazing. Perfect production, great bass, vocals that howl and shreik and even some Gregorian-like chants! But if I remember correctly, I didn't hear any solos.. but there could be!

You could also check out Secrets of the moon.

It hardly sounds like Keep of Kalessin, but Weapon's Para Bhakti... Salvation EP is no slouch when it comes to the leads and solos department. Super melodic it isn't, but the leads and solos greatly enhance the atmosphere and do have their more melodic moments. Weapon are composed of technically capable musicians, so the playing is far from sloppy, but the production still retains a degree of rawness to it. The clarity isn't really hurt, though it is by no means as clean as Kolossus. Highly recommended.

Zyklon! It's got a bit of a death-thrash element to it, but damn, in terms of production and solos they are RIPshit, particularly Disintegrate, but also Aeon.

Similar to Zyklon is Soul Reaper.