Hi
Apple's new North Carolina datacentre is due to come on-line by 'the end of the year':
https://www.macrumors.com/2010/07/20/apples-massive-north-carolina-data-center-ready-by-end-of-year/
What have Apple's technical strategists planned to fill it with?
1. Could be Mac Mini Servers?
But the guys who rack them up by the hundred are mostly web hosting operations who are operating in a very competetive marketplace. Apple don't have such an immediate constraint.
2. Could be a bespoke box along the same lines as Google have had built:
http://news.cnet.com/8301-1001_3-10209580-92.html but given Apple's hardware profile I would guess they'd want a more robust design that they could sell in their general marketplace.
3. So that means a new super-X-Serve box. I would guess, with its design finalised just-in-time to make them before they get installed. More efficient, more powerful (more cores?)...
So:
We all get a corresponding new Mac Pro design 'more efficient, more powerful (more cores?)' at the same time they go into production as the server box.

Much later this year...
Some further points:
1. Apple did a complete mobo redesign after less than a year between Rev a and Rev b of the original G5 Mac Towers, although the CPUs remained 2GHz max (with a die shrink), so they are quite ready to rework the tower's guts if they feel it appropriate.
2. With Light Peak on the horizon a huge rethink on form factor is likely as that rewrites the rule book. But that's not 'real soon now', so any Mac Pro redesign this year is sort of an interim project - certainly not going to last for 7 years...
3. Apple snuck the 2009 Mac Pro pricing increase in when Steve was flat out on the operating table. I guess that was Tim Cook's way of discarding any lingering nostalgia that Apple's CEO might have felt for his roots. "You want something? It costs..."
4. About 3 years ago (can't find the link) Apple indicated that they were no longer going to advertise any new Pro App hardware through mainstream media (TV superbowl ads etc), but rather they were going to capitalise on the hugely valuable word-of-mouth process that their professional users brought to the party.
That worked fine for software - Leopard, FCS 2, Logic 8/9 etc, and the 2008 Mac Pro but it came a cropper over the MacBook FireWire port debacle - petitions and the like
Apple recovered (reinstating a FW port on the revised unibody MBP), but I'm sure they look over their shoulder more now than they did in the past...
As Steve so often tells us 'it hurts' if we don't like his products...........
So I do think they take notice
But 'they know best'...........