Hey Steve,
IIRC, 3M was the first to offer backcoated tapes. I could swear that there was a "3M Sound Talk" that explained the benefits but I can't find it right now (these were compiled, and scanned by Jay McKnight and are available for download from AES, free for members).
According to my charts, the first backcoated 3M tape released was 151 in 1964. I think the first backcoated tape I bought was in the early 70's and it was Scotch branded.
Perhaps my memory is clouded on the subject but I'm sure there must be a technical paper regarding the subject in the AES archives.