According to a forum thread [Google translation] posted to Chinese site WeiPhone.com last week, the new 13-inch Retina MacBook Pro will indeed be launching late this month. The report claims that it will carry the same thermal design as the larger 15-inch model, but with only one contact pad indicating that it will not include a discrete graphics chip.
The source reports that the 13-inch model will include an “unprecedented” battery design and offer the same set of ports seen on the 15-inch model: MagSafe 2, a pair of Thunderbolt ports, a USB port, and a headphone jack on the left and a USB port, an HDMI port, and an SD card reader on the right.