Apple's tablet computer rumours surfaced again this week with a report claiming the device exists and is being manufactured for Apple by Asus.

Crave reports ‘insider sources’, who claimed: "Asus is helping Apple build a tablet PC." The magazine notes that Asus is one of the Far East vendors who build portable Macs for Apple.

The report claims the new tablet Mac will feature an all-new design. Looking to the present, it seems likely such a machine will run Mac OS X 10.5 and could potentially use the same multi-touch technology Apple employs in the iPhone and iPod touch.

The tablet Mac rumours are nothing new. Exactly 12 months ago, Australia's Smarthouse magazine published claims that Apple had built a, "fully working prototype of a Mac tablet PC."

That report claimed the device to have been designed to handle third-party applications, such as home automation software and security cameras.

The 2006 report stated the new tablet Mac would ship in mid-2007. While this didn't happen, it may be of consequence that Apple had originally intended to ship Mac OS X 10.5 Leopard in mid-2007.

If the purported tablet Mac required Leopard to be market-tested before it shipped, and if these rumours have substance, then this suggests the system may see the light of day early next year.