I am looking for a band that has all of the unique and creative aspects of a band like Opeth but is less heavy like Liquid Tension experiment. I would prefer for it to be instrumental, but if there are vocals I would prefer for them to be clean. If my request is vague tell me, and I will try to elaborate.

Thanks in advance

Well i got something for you, in fact i like very much both bands, i don't know if you would like it but i advice you: "Sepia Dreamer", hope you find it and hear it, regards!!!

Tyr, if you consider them Prog.

JT Bruce ...especially Universica

Equirhodont...definitely creative, though I don't know if it's along the lines you requested. It's a somewhat weird prog project by Root-singer Big Boss with a dark vibe and a strange, otherworldly story to their two concept albums. Heavy at times, but the vocals are clean.

And maybe Giant Squid's newest output, "The Ichthyologist". It's not so heavy like their debut and with quite a few psychedelic influences from the old times on top of the usual (not so sludgy anymore here) progressiveness. Not instrumental, but male/female vocals are clean.

Symphony X's most recent album, Paradise Lost, may be what what you are looking for, a very clean progressive metal album with extreme musicianship blended in well.