I foresee Apple's stock taking an even bigger hit (as if it hasn't already) if they do not release any hot/attractive products in the Spring/Summer. Remember, Apple is a corporation and needs to satisfy not only its consumers but its shareholders as well. Going 2 quarters into 2013 without some "revolutionary" product will no doubt make their stock unattractive to the markets. An update to all their mobile devices (iPhone, iPad, iPad mini) this past fall will boost this quarters numbers no doubt, but sales only continue to trickle down from this point.
Updates to the Mac Pros, iMac, Macbooks, OSX software, etc. should be expected in Spring 2013 as the new Intel Haswell processors will be available. However all those products COMBINED do not even get close to iPhone/iPad sales and not everyone updates their computers year to year. Certainly not when their desktops/laptops cost a whole lot more than a $500 dollar iPad. Hottest products will still be the iPhone and iPad.
If I was in Apple's shoes, I would release the iPad Mini Retina before Summer 2013, but just sell it at a premium. Similar to how Apple sells the iPad 2 and the iPad 4 at different starting prices, the current iPad Mini can be sold alongside the iPad Mini Retina (with the Retina obviously commanding a greater price).
With the IGZO display technology, slightly thicker battery (similar to how the iPad 3/4 is thicker than the iPad 2) and perhaps the A5X processor with a die shrink, I'm sure they can create an iPad Mini Retina if they wanted to. Unfortunately I feel that this would also create what I felt my iPad 3 always was, a compromised device.
As witnessed with the iPad 3, Apple will push out a product simply to add Retina and satisfy consumer demands. The CPU power was no better than the iPad 2 it replaced, yet it still sold like hotcakes because it was Retina. If the iPad Mini Retina received the A5X processor, it would be able to push the Retina display, but it's CPU would roughly match the A5 in the current Mini and would be less powerful than the iPad 4. This helps the iPad 4 justify it's current price tag.
Later on when Apple refreshes the iPad 4 in the Fall of 2013 with a new (hopefully slimmer) design and an "A7" processor, this leaves room for the Ipad Mini Retina to receive a spec bump with an A6X.
If Apple just so happen to delay the iPad Mini Retina to Fall 2013, then in the meantime they might probably have another device (Apple TV?) to fill the void. Who knows...
Also, if anyone has doubts about cramming the iPad 4 display in a 7.9" size, HTC is already releasing a phone with a stunning 5" 1080p display. This equates to 440 PPI. This phone will probably be announced next week during a HTC / Verizon event on November 13th.
Link:
http://www.theverge.com/2012/10/17/3515158/htc-shows-off-stunning-5-inch-1080p-j-butterfly-phone-in-japan