Along with all the buzz around clouds, the Open Group in conjunction with the Jericho Forum has started a project to define a reference architecture for a collaboration oriented architecture. The collaboration oriented architecture is the Jericho Forum's response to the business driver of de-perimeterisation and the technical driver of cloud computing. The Jericho's existing paterial on the COA is here. The reference architecture is intended to drive the existing collateral on the COA to the next level, to form a more complete description of what is required and how it will meet organisations' needs. I'm facilitating the group within the Open Group Security Forum. If you're a member of the Open Group you can contribute to the COA reference architecture. Here's a link.