On Friday, VMware release the first version of VMware Studio. As described on the Studio page:
VMware Studio 1.0 enables software developers and hardware appliance vendors to build customized virtual appliances that can be shipped in industry standard Open Virtualization Format (OVF).
While VMware Studio is designed for ISVs to author their own virtual appliances, I have a number of enterprise customers who are interested in this as well. Either for creationo of internal virtual appliances as official versions of a software stack or as building blocks for creating a virtual machine library. Studio is more suited to the former versus the later, other VMware tools like Lab Manager and Stage Manager have library functionality built into them which are better suited for hosting an enterprise VM library.
VMware Studio is available as a free download from the above link.