progressive yet technical thrash

Not thrash you want, but those are pretty good bands, especially Communic who kicks major asshole. Check out Sieges Even maybe?
 
Did Sieges Even used to be thrash before The Art of Navigating By the Stars?

EDIT: never mind, I reread your post V. Sieges Even are great, although I am only familiar with their more recent material.
 
Dark Empire play a weird blend of technical, progressive thrash with strong power metal vocals. Great stuff.
 
Did Sieges Even used to be thrash before The Art of Navigating By the Stars?
I think I already mentioned in another thread a while ago that their debut album "Life Cycle" was technical thrash metal in the vein of Watchtower's "Control And Resistance". The two albums which followed - "Steps" and "A Sense Of Change" - have nothing to do with thrash metal, yet are highly recommendable.

As regards technical/progressive thrash metal, I'd recommend:
Mekong Delta
Coroner
Toxik
Watchtower

Also try:
Hades - "Resisting Success"
Voivod - "Dimension Hatröss"
 
In addition to the ones Burkhard mentioned above...

Anacrusis (Manic Impressions and Screams & Whispers)
Depressive Age (First Depression and Lying in Wait)
Realm (Endless War and Suiciety)
Skeptic Sense (Presence of Mind)
Thought Industry (Songs for Insects)