As soon as I saw the topic name:
The Fractured Dimension - Towards the Mysterium
It's some kind of progressive, avant-garde piano based music with lots of guest guitarists such as Ron Jarzombek. Some parts are non-metal, some are not non-metal...
Their MySpace Page
All the songs on there are old mixes of stuff from their album.
May not fit the description you gave perfectly, but definately give them a try.
Elton John
Akphaezya - Anthology II
unexpecT - In a Flesh Aquarium (Ya, I know, I'm annoying with these two band, but it's only because they fit in all these recommandation threads!)
5uu's - Abondonship (non-metal)
Arturus - The Sham Mirror
Morgul - Sketch of a supposed Murderer (Your best gest, it is dark and depressing)
Katzenjammer Kabarett - Katzenjammer Kabarett (non-metal, Death rock)
Tub Ring - The Great Filter (non-metal)