Three Symbian^4 UI mockups found their way to the surface. As compared to previous leaks, now there are semi-transparent menu overlays and richer variety of sample homescreen widget. But the pictures show only a small part, the Concept Proposal document offers a lot more suggestions though.

The semi-transparent menu bar overlay is the most notable change we can see. Next are the nicely designed clock and to-do widgets, and that’s all you can conclude from these new images.

The User Interface Concept Proposal found alongside the UI design mockups include renewed layouts, non-standard shaped homescreen widgets with free movement and placement, improved task-switcher, redesigned Settings and Power menus.

The renewed layouts concerns the titlebar region, which may contain three interactive elements – universal signal and battery indicators, app title menu with drop-down element for more options and a back button. The titlebar and the bottom menu bar can be set to auto-hide on a predefined interval.

The Symbian^2 and ^3 are expected in Q1 and Q4 this year, while the Symbian^4 shown here is scheduled for the early 2011.