The release of the iPhone last year has not only won Apple plenty of new customers with deep pockets, but also raised the bar several notches for other phone-makers, including the company behind the ultra-successful Blackberry.

Rumours that Research In Motion (RIM) is about to release a touchscreen BlackBerry appear to be gaining credence now that yet another patent filing describing just that has been discovered.

Touchy Blackberry

In a patent entitled 'Hybrid Portrait-Landscape Handheld Device with Trackball Navigation and Qwerty Hide-away Keyboard', RIM outlines plans for a device that features a decent-sized touchscreen and a physical keyboard as well.

The fact that the prototype offers both a physical and virtual keyboard is an interesting development. It reflects the attitude of the company's CEO Mike Lazaridis, who said last year that "the iPhone has severe limitations when it comes to effortless typing".

RIM did not comment on the patent leak, saying it currently has no plans to release this device or any other offering a touchscreen. But given the current state of the mobile phone industry and how practical this prototype appears, look for more on this story soon.