There have been rumors for some time now that Apple’s MacBook Pro line would be getting an update sometime this year. While earlier reports suggested April, that obviously didn’t happen. Given how deep we are into May, a launch this month doesn’t seem likely either. If, as seems likely, Apple does have a revamped MacBook Pro in the works, sometime during the summer seems likely.

The summer launch of the new MacBook Pro appears to have been confirmed by “trusted sources in Apple’s supply chain,” who told 9to5Mac that they got their hands on components of the new computers. It seems that the new MacBook Pro will be getting USB 3.0, a thinner form factor, and, at long last, a retina display. According to the sources, the new MacBook Pro will not borrow the design of the MacBook Air, but will simply be the same basic body design, just thinner. Of course, in technology as in dieting, thinness comes with a cost. It seems the new MacBook Pro will be losing its optical drive. That’s right: no more installing software from a CD or DVD, no more DVD playback, no more importing CDs into iTunes. If you want to do any of that, you’ll have to spring for an external optical drive (which Apple will be happy to sell you for $79 plus tax). Consequently, the new MacBook Pro will also replace the disc eject key with the power key, a la the MacBook Air (have fun getting used to that).

The big news, of course, is the retina display. There has been speculation since the launch of the iPhone 4 in 2010 that Apple would be bringing retina display technology to its entire range of devices. As you might expect, this appears to be going in order of screen size (roughly). The 9.7-inch iPad got a retina display earlier this year, and now it looks like the 15-inch MacBook will be getting it as well. Presumably the 27-inch iMac will eventually join the party we well, but that may be awhile yet. It’s not clear yet what the exact pixel dimensions of the MacBook Pro will be, but the new iPad is 2048×1536, so the MacBook Pro will have to be bigger than that to keep the “retina display” title.

9to5Mac’s sources were not able to provide much in the way of pricing or release date information, nor whether the 13- and 17-inch MacBook Pro models would be getting the same treatment as the 15-inch model. There might, however, be some clues in a separate report published the morning by DigiTimes. Their own “sources from the upstream supply chain” claim that Apple’s orders of components for the MacBook Pro have been increasing since March, and that they should rise dramatically in June and July, suggesting a mid-summer launch for the new MacBook Pro.

As you probably know, something else Apple-related will be happening in June as well: WWDC 2012 is scheduled for June 11-15. There are rumors of several new software products set to be unveiled and/or launched at this year’s conference, including iOS 6 and OS X 10.8 Mountain Lion.

If Mountain Lion is set for a June release, what better way to celebrate that than by rolling out a new update to the MacBook Pro line? With less than a month until WWDC starts, it won’t be long until we find out.