Regarding transposing instruments, there was a proposal floated about in the 1960's and 70's to treat F recorders as transposing instruments so that elementary school students would only need learn one set of fingerings and the sheet music would be transposed to take care of the pitch difference. The proposal never really went anywhere, probably because recorder players quite routinely play music line written for the voice immediately above or below their instrument's, so transposing on the spot could have become a problem.