As content as you may be with your MacBook or MacBook Pro laptop, things may be about to change.

According to AppleInsider, sources close to the story have stated that the 13" MacBook will undergo the most significant changes, losing its plastic enclosure for a more eco-friendly set of materials such as aircraft-grade aluminum and stainless steel.

The move, if pushed through, would make an effort made by CEO Steve Jobs to create a "greener Apple," as well as mark an end to the white enclosures that began to be phased out by the launch of the original iMac in 1998.

Sources have also stated that the MacBook Pro is due for aesthetic revisions and could take on a look with influences from the August 2007 aluminum iMacs and the recently-released MacBook Air. The end result, according to sources, would be a more uniform product matrix in terms of design and material usage.

Current guesses as to what will be changes include matte black portions on the casings, oversized trackpads and the adoption of the MacBook Air's keyboard by the MacBook.

Although the footprint of the 13-, 15-, and 17-inch systems will likely remain pretty much the same, Apple will reportedly be trimming the edges. Such an effort would be similar to the redesign worked into the MacBook Air and the rear of the aluminum iMacs.

Compelling the Cupertino-based firm to introduce radical revisions across its notebook lines at this juncture are two primary factors. The first is the company's industrial design cycle, which typically spans 18-24 months. Though popular, neither the MacBook or MacBook Pro laptops have undergone a major aesthetic or structural revision since Intel chips were adopted in January of 2006.

The design of the MacBook Pro, though familiar, largely retains the form factor of the late PowerBook G4, only 20% slimmer.

Also contributing to the change are logic board changes that may push Apple to re-assess and modify its notebooks' internal working. The MacBook and MacBook Pro laptops are set to receive Intel's "Montevina"-based processors, which require a new "Socket B"-style logic board. The Montevina serves as the second generation of mobile Penryn chips and will boast a 1066 MHz front-side bus with a clock speed between 2.26 and 2.8 GHz.

The Intel roadmap calls for Montevina to be release in June, just around the time Apple holds it Worldwide Developers Conference in San Francisco.

Stay tuned for more news on this as it becomes available and if you've heard anything interesting, let us know over in the comments or forums.