SF Sorrow would meet the definition and is a great album. But it's already forgotten by the zeitgeist.
I was trying to think of an reconisable genre term so I changed chamber-pop to psyche-pop, so The Yardbirds weren't really what I was thinking about. I doubt they'll be remembered in twenty years other than as a footnote in the Led Zep story who'll be token representative of seventies hard rock.