Design concept art has been revealed this week that hints at the future user interface for Windows 8.

ZDNet uncovered a large number of design documents submitted to Microsoft by Manoj Manduva. Microsoft’s Indian Research and Development team worked with Manduva to produce concept designs for Windows 8. Some of the designs reveal a “flip” feature that switches UIs from classic to advanced modes. One of the slides also describes a multiple desktop scenario for Windows 8. “Manage multiple desktops and flip between them using short cut key.”

The next set of slides describes a concept “skew window management”. The feature seems similar to Windows Vista’s Flip 3D interface and allows users to leap backwards and forwards through windows and folders. ZDNet suggests that the UI could be used for Microsoft’s touch-based computing in Windows 8. Microsoft is reportedly working on a tile-based user interface codenamed “Mosh”. Microsoft has recently started compiling Milestone 3 builds of Windows 8 and is expected to ship an early beta in September at PDC 2011.

Microsoft may be preparing to demonstrate its Windows 8 Tablet UI as early as June, according to reports on Monday. Microsoft has a habit of introducing new technologies at the Wall Street Journal’s D: All Things Digital Conference, which will run from May 31 to June 2 this year. Bill Gates introduced Microsoft’s Surface computer in 2007 and the company demonstrated Windows 7 multitouch in 2008. It’s possible that Microsoft might be planning to demonstrate a technology preview of Windows 8 Tablets at the conference this year.

Microsoft may introduce Windows 8 ARM based tablets ahead of a full desktop release according to recent reports. Microsoft’s competitive tablet strategy is believed to be further along than expected. Dell’s recently leaked Tablet Roadmap revealed that the OEM has marked Q1 2012 as its date for a Windows 8 based slate. WinRumors understands that Microsoft has been working on an ARM based version of Windows for nearly a year and that it is laboring hard to bring this to the market as soon as possible. Microsoft has previously promised a “major revamp” of Windows for slate applications, that will come in the next version, Windows 8.

Microsoft has so far been extremely quiet on the Windows 8 front. Windows Chief, Steven Sinofsky, took to the stage at the Consumer Electronics Show in Las Vegas in January to introduce a technology preview of Microsoft’s Windows ARM support and show off an early build of Windows 8. Microsoft is partnering with ARM-based manufactures NVIDIA, Qualcomm and Texas Instruments to produce new Tablet devices. Rumors suggest that Microsoft will create a dual-UI for Windows 8.

Steve Ballmer has described the next release of Windows as the company’s “riskiest product bet”. It is understood that Microsoft will feature deep cloud integration into the future OS to realise its vision of “three screens and a cloud”. One Microsoft employee recently said he believes Windows 8 will be the “most important Windows ever shipped.”