In case you missed it - the latest Product Use Rights (january 2013) now includes a note under Additional Terms #3, page 82
"3. Each user may also use one of the five activations on a network server with the Remote Desktop Services (RDS) role enabled" (see screenshot below)
Update January 22nd, 2013 Its important to emphasize that the Office 365 ProPlus bits will not install or run on a server with RDS enabled, but the updated PUR enables organizations to Volume License bits (Office Professional Plus 2013) in lieu of Office 365 ProPlus on RDS servers. Any user licensed for Office 365 ProPlus can access an RDS-hosted install as one of the 5 concurrent installs allowed per user (blog post title adjusted to reflect this update)
Update 1 March 18th, 2013. As per the Microsoft Product List March 1, 2013 page 97:
"Media Eligibility with Remote Desktop Services (RDS)
If the user to whom you have assigned an Office 365 ProPlus license uses the software on a network server with RDS role enabled, in lieu of installing a copy of the software provided with Office 365 ProPlus on one of the five permitted devices pursuant to the Product Use Rights for Office 365 ProPlus, that user may: 1) install one copy of the Office Professional Plus 2013 software on a network server and 2) access the Office Professional Plus 2013 software from any device. Upon termination of your Office 365 ProPlus subscription you must uninstall Office Professional Plus 2013 software from the network server"
Update 2 March 18th, 2013. As per the Office 365 ProPlus service description:
"Office 365 ProPlus is supported on user-dedicated virtual desktop infrastructure (VDI). To use Remote Desktop Services (RDS), you must use a volume license version of Office Professional Plus 2013, which is available on the Microsoft Volume Licensing Service Center. For more information, see Microsoft Volume Licensing Product Use Rights".
Note: the above is valid for the upcoming version of Office 365