iPhone 5 rumours posit 4-inch screen and slide-out keyboard

Just because Mobile World Congress is taking place doesn't mean the iPhone rumour mill is going to stop churning out speculation-flavoured flour. Two separate reports today have predicted the form factor of Apple's next-gen iPhone 5 smart phone.

Firstly, DigiTimes claimed -- via the obligatory 'upstream component suppliers' sources -- that the iPhone 5 will have a 4-inch, rather than 3.5-inch, screen. The increased screen size is apparently part of Apple's attempt to go head-to-head with Android devices like the Samsung Galaxy S II and upcoming big-screen models from Sharp and Acer.

Secondly, Taiwanese site tw.apple.pro, which has been a regular source of Apple leaks in the past, went further and said three prototype designs are under consideration for the iPhone 5. 

AppleInsider translated the report. Apparently, one of these prototypes is the same as the iPhone 4 but with a beefier battery and better camera, while another has a slide-out keyboard: a first for the iPhone. We're treating the latter claim with a pinch of salt, although Apple could be experimenting with the idea, with a view to attracting business folk to its smart phone at some point in the future.

Separately, there's another iPhone nano rumour in town this morning, and it's a corker. After Bloomberg and The Wall Street Journal reported on Apple's plans to launch a cut-down version of its iPhone later this year, Cult of Mac has published its own claims to this end, with some fascinating additional details.

Its report claims the iPhone nano will have "no memory for onboard storage of media... it will have only enough memory to buffer media streamed from the cloud". That means streaming everything from Apple's MobileMe service, which The Wall Street Journal tipped for a major revamp this summer to focus on music, videos and photos.

What we don't understand about this particular rumour, though, is how the iPhone nano would run apps without any memory. And what the flip would you do with it when you're out of reception on a plane?