If they do announce something then I would expect some shipping delays. We've been hearing about events comming and hardware comming for ages now though on all three of these products, so I wouldn't be getting excited if I was waiting.
Although I have been keen to point out that Apple released Mac Pros 6 and 8 weeks after Xeons were launched previously, that's all we have to go on after all, I will admit it is a bit different this time. The launch date is where it is to meet a Q1 release and let board manufacturers clear inventory and let Intel sell their Penryn processor stockpile from what I've heard. So it is possible they have a large inventory of Xeon 5500 processors ready to reach vendors. I'd forget about any special treatment for Apple stuff though, that screams of wishful fanboi thinking, Apple are a small customer for Xeon processors. Though if they buying several hundred thousand in advance of the same SKU that might work in their favour.