Apple delayed iTunes 11 once already to make sure that everything was perfect in the latest version. The new version of iTunes will see the removal of Ping and the revamping of the iTunes store layout. Part of the store layout change includes having pictures of the artists available for browsing by shoppers.
And that is the part where today's rumor comes from. German music distribution service Feiyr sent out an e-mail (seen above) to artists. The e-mail states that iTunes 11 is "about to be released within the next days." Sure, next days isn't an exact timeline, but Apple is probably pretty close to getting iTunes 11 out the door.
Besides, they only have 9 more days to meet their deadline of the end of November. It's highly unlikely that Apple would want to delay the product yet again. So, on the early side, we should be able to expect iTunes 11 pretty quickly. On the late side, it looks as though Apple is still on track for meeting the deadline of end of November.