Answer: Yes! That is called "scordatura," and goes back at least to the 17th century, not only in lutes but in bowed strings. Heinrich von Biber's Resurrection Sonata (1675) has a movement in which the violin is tuned to g g d d instead of g d a e, and in the 18th century Bach's Suite No. 5 for solo cello uses an A string(the upper string) tuned down a step. More often the lowest string would be lowered a step, or the upper string raised one. Among modern composers, Bartok used it in the last movement of his Contrasts, requiring the violin to sometimes be tuned to g# d a eb (!). Traditional fiddle players have long used scordatura too. Though I don't expect they call it that. And getting further out of the classical realm, guitarists like John Fahey sometimes tuned in "open" tunings so that all notes of the guitar formed a single chord.