Designer Martin Hajek, who often creates renderings of upcoming devices based on rumors, has mocked up what a thinner 15-inch Retina MacBook Pro with some MacBook-style design elements could look like.
The design, which also includes a conceptual version of "macOS," features smaller side bezels and a much thinner chassis, one that's not quite as thin as the Retina MacBook but much thinner than the Retina MacBook Pro today.
Hajek's slimmed-down Retina MacBook Pro concept comes amid rumors Apple is working on "ultra-thin" 13 and 15-inch "MacBooks." That rumor suggests new MacBooks are being developed that feature a design similar to the existing 12-inch MacBook that are also thinner than the existing MacBook Air.
The rumor, which is the second we've heard about thinner notebooks, does not make it clear if the MacBooks will belong to the MacBook line, the MacBook Pro line, or the MacBook Air line. Because the fate of the MacBook Air line is in question and the MacBook line already has a 12-inch MacBook, it's entirely possible the rumor refers to thinner MacBooks that are in development as part of the MacBook Pro family.
It is not clear when these thinner 13 and 15-inch mystery MacBooks will launch if they are indeed in development, but rumors suggest they will debut at the end of the second quarter or in the third quarter, pointing towards an introduction in the summer or fall months.