A sort of rule of thumb, if you are looking for HD versions, anything dating from the Little Mermaid and newer, the official versions are the best you'll find (for what that's worth), and anything older you'd want to look for HDTV versions on the newsgroups or torrents sites.
HDTV broadcasts typically aren't "restored" which is where Disney has been going wrong.
That said, I haven't come across an old iTunes or HDTV rip of Jungle Book.