File this one in the "sources said" folder. But I've now heard from three of my contacts that Microsoft has completed and is testing internally a version of Outlook that runs on Windows RT-based devices.
This "Outlook RT" would run on Microsoft's ARM-based Surface RT devices, as well as any/all other ARM-based Windows RT tablets and PCs.
Here's the catch, though: According to two of these three sources, when/whether Microsoft will make Outlook RT commercially available is not yet decided. This might not ever happen, these sources stressed.
Again, according to these sources, there's supposedly some internal back-and-forth between different teams as to whether Microsoft should or shouldn't release Outlook RT.
Microsoft currently has its own Mail client for Windows 8 and Windows RT -- a product that is not seen as very robust or solid by many of us Surface RT/Windows RT users. The Windows RT Mail client is not even as good as the Mail client that's part of Windows Phone, many of us feel.
Quite a few of us would rather have the option to run Outlook on our Surface RTs and other Windows RT devices. But for now, Microsoft doesn't include Outlook as part of the Office Home & Student 2013 RT suite that it bundles with the Windows RT operating system. Only Word RT, Excel RT, PowerPoint RT and OneNote RT are included. (It's worth noting these four apps are Desktop apps, not "Metro-Style"/Windows Store apps. There are only two members of the Office suite that currently exist in Metro-Style form: OneNote and Lync.)
A quick aside: Microsoft officials have not said the company plans to bundle any kind of version of Office with the coming Surface Pro devices. But there has been scuttlebutt on Twitter that Microsoft could make some kind of trialware/offer for Office 365 Home Premium available for Windows 8 systems, including Surface Pros.
I, myself, would gladly pay for Outlook RT if I could buy it. If it isn't a Metro-Style/Windows Store app, though -- and I don't know whether it is or isn't -- I'm not sure how Microsoft would make it available to us Windows RT users. Maybe as part of an overall refresh of the Mail/Calendar/Messaging set of apps or a refresh of the Office RT suite? (Update: Another option, as @Shmuelie notes in the comments below, would be simply via Windows Update.)
Distribution isn't the only open-ended question here. Supposedly there is disagreement in the Microsoft ranks regarding whether it would be in the company's best interest to do this.
One contact of mine said that there are some inside Redmond (the Windows unit) favoring the preservation of the integrated Windows 8/Windows RT Mail/Calendar/People app bundle as is. Some people in this camp are said to favor renaming the existing Windows 8/Windows RT Mail app to "Outlook." (Given we already have three different Outlooks -- the current Office Outlook, Outlook on Windows Phone (if you have your built-in email set up to display Outlook and/or or Outlook.com) and Outlook.com -- I'm really hoping this won't happen. Which probably means it will.)
Supposedly others (in the Office division) are bucking to release the "real" Outlook for Windows RT as a separate, native application.
It will be interesting and telling to see which way Microsoft goes on this one. I think having the real Outlook natively available on Surface RT and Windows RT could boost the appeal of those platforms. But maybe Microsoft would rather hold back Outlook as something only available on Windows RT to those willing to pay monthly/annually for an Office 365 Home Premium subscription?
I asked the Office team for comment on this and was told by a spokesperson there was nothing further to say beyond the fact that Office Home & Student 2013 RT does not include Outlook. The spokesperson added “Microsoft Office doesn't come with Surface 8 Pro but can be purchased separately.”