Apple has quietly—oh, so quietly—launched the iPad mini with Retina Display on the online Apple Store. This marks the softest launch we've seen for a major new Apple product, suggesting that supply will be quite limited.
Currently on the home page of the Apple Store:
iPad Air and iPad mini with Retina Display
Currently the Apple Store shows availability at 5-10 business days, and that was the case within seconds of the Store coming back online.
Recent rumors have said that supplies of the display Apple is using with the iPad mini with Retina Display are in short supply, and would limit availability of this device until early 2014. Launching the device without pre-announcing the date, without holding a launch event, and without even issuing a press release strongly backs up those reports.
Add in initial availability at 5-10 business days, and, well...yep.