Shipping times for the Mac mini
have slipped to between five and seven days at Apple's online store. Typically, other Macs on the store are shipping within 24 hours. Such delays are often a sign that Apple is reducing supplies in preparation for a product update.
The only Mac updated during Apple's usual June refresh was the MacBook Air, although Apple did tease a forthcoming Mac Pro update. A new Mini would presumably upgrade to Intel's Haswell platform, and offer new storage and connection options.