Orchestrated Rock...Uriah Heep and others

I guess you mean the use of strings. As far as classic rock goes, Days of Future Passed by the Moody Blues is a great one, and in newer stuff, Beck often makes good use of strings on some songs. (Morning Phase) 

Just off the top of my well abused & old as dirt brain I recall:Pink Floyd,Led Zeppelin,The Scorpions,White Snake,UFO,ELO,EL&P,The Beatles,The Beach Boys,Deep Purple,Queen,Metallica,Alan Parsons Project,Supertramp,Kansas,Jethro Tull,Rush & Stevie Nicks all using full orchestras at one time or another...I'm sure just about EVERY decent rock band did this as well...

Procol Harum - 'Live in Concert with the Edmonton Symphony Orchestra'

Elton John - 'Live in Australia with the Melbourne Symphony Orchestra'

Electric Light Orchestra - 'Eldorado'

Metallica - 'S&M' 

4 that I can think of offhand.  Procol Harum was the earliest in 1972.  ELO was a year or two later.  

Rich

The moody blues ,if you define orchestration in detail that will define exactly your prospective.

Deep Purple, Concerto for Group and Orchestra

And lots of Keith Emerson's pillaging of classical music's back catalogue!