A leaked Microsoft presentation appears to show off the possible UI for what I call Office Touch for Windows, the Modern suite of mobile apps that will arrive later this year. And if this is correct, this presentation further appears to show that an Outlook app will be part of the suite as well.
There are some interesting comparisons to be made between the images seen here—which could obviously just be prototypes, or whatever—and the shipping version of Office for iPad. And even if they are legit, they could of course be out of date. So for now, let's just take a look.
Thanks to Lairent F. for the tip.