It was a bit of a one-off and not even Green Carnation sounded like that before or after, so I cannot honestly recomend another GC album if LoD,DoD II is what you are looking for.
Green Carnation's previous incarnation
In The Woods... had a similar feel, but show more King Crimson / early Pink Floyd influence - Omnio or Strange In Stereo are worth a listen
Or perhaps early Pain Of Salvation - One Hour By The Concrete Lake or The Perfect Element (part 1)
...as a more left-field suggestion Diabolical Masquerade's "Death's Design" - that's more extreme and very experimental (advant garde black metal) but equally as epic ...