Rumours surrounding the arrival of an ultra-thin Mac notebook moved a step closer to reality today with the latest report from Apple Insider. It says models with a gunmetal grey aluminium enclosure have been seen 'floating around' Apple's Cupertino, California campus. Which is a neat trick, even for Apple.

What's not clear is whether these magically levitating notebooks are the same models featuring solid-state drives (SSD) that site has also been talking about - or just revamped MacBooks.

An ultra-thin sub-notebook has been lusted after by Mac fans for years - and is high on the list of products they'd like to see Apple introduce at Macworld Expo next month. Adding fuel to the fire is the new that Apple had planned to launch a sub-notebook last June when Mac OS X Leopard was originally scheduled to launch.

Any new portables are likely to sport Intel's new 45nm Penryn processors, which are also coincidentally being launched next month. Floating optional.