I had a public school in Denver ask me this question since they had a rich student portal on prem but wanted to take advantage of the new 1TB quota which is no cost for faculty, staff and students with the A2 Office 365 Education SKU plans.
This is how we currently leverage OneDrive for Business (ODB) at Microsoft with the split hybrid SharePoint scenario with OneDrive for Business in Office 365 and sites locally. We are also creating net new SharePoint sites inside of SharePoint Online as well.
With the newly released SP1 for SharePoint 2013 Server, there is a hybrid OneDrive for the Business in Office 365 and SharePoint sites on premises option.
Please see steps to configure this SharePoint 2013 hybrid scenario here.
We are looking into doing the same thing. However I can't find any good information on how that affects features like "News Feeds", Following, and Tasks on the users MySite when it moves to the cloud. Are there any lost features?