The Mac site has analysed past iTunes releases, and states that "two were released on Sunday, fourteen on Monday, twenty on Tuesday, twenty five on Wednesday, sixteen on Thursday, and seven on Friday. That means that Wednesday is the first most likely day for a new iTunes version to be released, followed by Tuesday, then Thursday."
Given that Apple is more likely to release it on a Wednesday, the site also states that of the five versions of iTunes released in November, none have launched later than 20 November. This makes sense as America celebrates Thanksgiving on 22 November 2012, and many staff - including Apple staff - will be out of the office. So it's better to ship it before, or it could slip until December (which would be embarrassing for Apple as iTunes 11 is already perceived as being late).
It's all guesswork, but sounds like good guesswork. We'll find out next week.