Microsoft CEO Steve Ballmer has strongly hinted that the company will craft a Metro-style version of the next Office suite.

"You ought to expect that we are rethinking and working hard on what it would mean to do Office Metro style," said Ballmer, when asked by a Wall Street analyst whether Microsoft is working on a version of Office for Windows 8's Metro touch-based interface.

Metro is the name Microsoft has given the tile and touch-based interface borrowed from Windows Phone 7, the smartphone operating system. The interface is the first thing users see when they launch Windows 8, and apps must be specially-coded to run in Metro.

A Metro style look-and-feel would be a massive change for Office, one that would dwarf the "ribbonisation" that set off a firestorm of complaints about Office 2007's new look. The criticism died down, and Microsoft later extended the ribbon in Office 2010 and Windows 7. It will ribbonise other components of Windows 8, notably the OS's file manager.

One analyst thinks that Office on Metro is a done deal.

"I think they need something in Metro to enable people to work on documents on tablets," said Rob Helm, an analyst with Directions on Microsoft. "They need something on ARM."

Microsoft is developing a version of Windows 8 that will run on ARM system-on-a-chip silicon to power iPad-style tablets. Because the company has said that the ARM edition of Windows 8 will not run legacy Windows applications, that leaves Metro-style apps as its software.

Steven Sinofsky, the president of the Windows division, reiterated that.

"We've been very clear since the very first CES demos and forward that the ARM product won't run any x86 applications," said Sinofsky. "If we allow the world of x86 application support like that, or based on what we call desktop apps in our start yesterday, then there are real challenges in some of the value proposition. Will battery life be as good, for example? Those applications aren't written to be really great in the face of limited battery constraints."

Helm envisions a Metro-style Office as being less than the desktop suite long familiar to users, but more than the current online Office Web Apps.

"With x86 dead in the water on ARM, Microsoft needs Office apps that allow for viewing and some light editing [on ARM]," said Helm. "Office Web Apps are perfectly positioned for that, but they don't support offline."

Helm believes that Microsoft will create a Metro edition of Office based on the work it's already done on Office Web Apps, and use Windows 8 APIs (application programming interfaces) to support offline work.

But the 'Metroisation' of Office won't kill the desktop versions of the suite, Helm continued. "Absolutely, the desktop Office will continue for Intel-based systems," he said. "Microsoft isn't walking away from that. Think of Office as desktop plus tablets with Metro."

Helm expects that the next desktop Office will look similar to Office 2010.

Microsoft has said nothing about a release timetable, the design or features slated for the next generation Office, but if the company follows past practice, it could ship a new version in 2012 alongside Windows 8 or in 2013, three years after the debut of Office 2010.

Talk of metro-ising Office isn't coming out of the blue. Several websites, including WinRumors, published screenshots earlier this year allegedly from an early build of Office that showed Metro elements in Outlook, the suite's email client.

Ballmer stated that Microsoft would give out more information on a Metro-style Office only when it's ready. "When we have something that we want to talk about, we will," Ballmer said.