#1
I'm looking for certain songs (or entire bands) that revolve around a sort of mysterious, astral sound. It's difficult to describe, but if you want to hear an example of something sort of simular, listen to 'buckethead - whitewash'. The songs have to be at least mostly guitar, thus radiohead doesn't count, nor is it melodic enough for me to count.

Anything you guys know of like that?
#2
Porcupine Tree maybe?

The song Up the Downstairs (as well as others) sounds like what you're after.