The new 17-inch MacBook Air [mockup]

Both 9to5Mac and MacRumors are citing sources claiming that the new 17-inch MacBook Pro will feature a non-removable battery. This is not an atypical design choice for Apple - it would be consistent with their approach to the iPod, iPhone and MacBook Air. What is strange, however, is that the new 13-inch and 15-inch MacBooks have regular batteries. So why would non-removable batteries be reserved for the Air and the 17-inch Pro, but not the two sizes in between? It surely implies that they have something in common.

And it doesn't take much imagination to work out what that thing in common might be. Especially if you've spent much of your life lugging around a 17-inch notebook. They're just too heavy. Sure, it gives you a bit of a workout, but it can also give you burn marks where the shoulder-strap of your laptop bag has eaten into your flesh.

And introducing a 17-inch sheet of glass to the mix isn't going to do anything to help with the weight problem. So perhaps Apple has something else in mind for their 17-inch model - something to set it apart from its smaller cousins, and something that may explain why it's spent a little longer in development.

Adding a 17-inch model to the MacBook Air line would introduce yet another category of mobile product. Something that worked out very nicely for Apple with the original Air - seemingly growing the overall segment rather than cannibalizing regular MacBook sales. As svelte 17-incher could be very popular with creative types like myself, and showy business exec types who want something to flash around in the airport lounge.

This is just speculation of course. If Apple was to take this approach, they may choose to introduce the 17-inch MacBook Air instead of, or in addition to a new 17-inch MacBook Pro. Next week's Philnote just got a little more promising.