I think they will begin shipping sometime in December, hopefully earlier. I think after promising 2013, then fall, then December;
2013 has both December and Fall parts. There is no conflict in any of those time descriptions. Fall ends on December 20. There is 3rd , 10th, and 17th of Tuesdays before then.
I suspect the limited supplies of both the E5 v2 and Thunderbolt 2 are a problem. If MBP with TB v2 controllers are selling briskly then the Mac Pro would slide later into Dec. If not going quite so fast then Apple might shift earlier if can get the E5 parts from Intel.
Intel has consistently said TB v2 was targeted for 2014 volume production. Sneaking the Mac Pro's out with pre-volume production parts would have gone more smoothly. Coupling in the higher volume MBP (and a few other vendors ) to that supply may be an issue.
I suspect mini and any possible "classic" MBP would be in 2014. Apple basically said their laptop line up was "complete" in the October roll-out. Complete for 2013 may be more accurate. If there is new "classic" MBP the mini is coupled to it in design/components so it too would probably slide.
I don't see Apple in a hurry to do new TB display either. If moving to TB v2 same limited controller constraint till 2014.
if it wasn't going to happen, they would have already issued a press release with an apology and a specific release date next year.
They don't have to backtrack on a date because they never gave one. The first target was all of 2013. Then it was Fall. Now it is Dec. All of those are ranges of dates. TB v2 wasn't suppose to come until end of 2013 and not show volume until early 2014. Likewise, Intel's now typically announce and then only limited ship Xeon E5 was going to roll into Q4 2013 also until that uncorked for volume shipments.
The only "planning" thrown at corporate here is aligning with the harps about how they need to see a roadmap before they buy anything because purchase approvals typically have long lead times.
June WWDC .... current Mac Pro going to get cancelled... if need one you have advance notice to buy one.
October ... new Mac Pro coming in 2 months... start lining up purchase approvals into the pipeline if want one "out of the gate".
There's also Christmas sales they want to obtain, with the Pro and the other products they will release at the same time, so the sooner, the better.
Holiday sales bubbles are overated as important for this class of product. It is far more an issue they:
1. Uncork Mac Pro sales in the EU... remember these folks have been on 'hold' since Feburary with nothing but refurbs/used. Apple needs to start selling something there sometime in 2013 pretty badly if this is going to be a viable product going forward.
2. Apple have stopped selling the current Mac Pro (3rd party channels still selling inventory) . Same hole that EU market went into in Feb is now worldwide.
3. Lots of 2005, 2006, 2007, 2008 Mac Pro about to be retired. pre-2008 already aren't tracking newest OS X. 2008's ... on verge of hitting vintage mark.
http://support.apple.com/kb/HT1752
A sizable fraction of those folks are moving to something. They need something before that 6 year 2008 model anniversary date. (yes, the vintage is keyed on when the replacement hit the market, but for folks who skipped the replacements... this born date is more indicative of last time they moved. )