Today we done the migration of our Internet Portal to the new Office 365 platform, over SharePoint 2010 online. We did a Master Page for SharePoint and we added some zones to add our WebParts. The work was very fast because "Office 365" has a fully SharePoint 2010 platform for us, it's great.
The best, is the capability to connect to our portal using SharePoint Designer 2010 to work there. It’s very important because in all developments of SharePoint is needed to add resources (images, CSS, JS and more) to create our design. Visit it here http://www.siderys.com/en/Pages/default.aspx