Recommending something to Monganaut, the man who alerted me to the spacerock lurking unidentified on Mob Rules...
As you are someone undaunted by the metal side of all things cosmic I would heartily suggest either of the Mammatus albums. Drones and massive grooves - doubtless you have them already, listen to them again perhaps.
Edit: Just found out they released a third album in 2013. Heady Mental. With a title that crass I had no choice but to buy immediately. Funny how chain of events start.
And yet another edit: An album with an excellent review on The Quietus written by the guy that I got pissed with last night. Too busy talking about the comprehensive slipper display in the shop opposite the pub we were in to talk about important stuff...