Preview at WWDC likely in June, followed by September launch.
13-Inch Retina MacBook Pro to Launch Alongside iPad Mini in October
The new 13-inch MacBook Pro will be sold in two configurations, with differing processors and storage, and will be available for purchase soon after introduction. Like with the 15-inch MacBook Pro lines, the 13-inch MacBook Pro with Retina Display will be sold (at a higher price) in addition to the current non-Retina display model.The site typically sources this information from early part numbers, suggesting that two higher priced configurations have already appeared in Apple's systems.
The new models line up with analyst Ming-Chi Kuo's predictions of a separate Retina display lineup that will sell alongside the existing MacBook Pro line.
Apple introduced the 15" Retina MacBook Pro in June, but retained the existing 15" MacBook Pro as well. Apple appears to be continuing this pattern by providing two 13" MacBook Pros -- one with a Retina display and one without.
The iPad mini event is reportedly scheduled for October 23rd.