We have just added the OVF build format to SUSE Studio! You can now easily create standards compliant and vendor independent appliances right from your web browser.
For those unfamiliar with OVF (Open Virtualization Format), it is an open specification for packaging and distributing software appliances, as defined by the DMTF VMAN standard. It is not tied to any particular hypervisor and is supported by many popular virtualization platforms. These include several VMware flavours (eg. ESX, Workstation) and VirtualBox. OVF is backed by Dell, HP, IBM, Microsoft, VMware, and XenSource.
To learn more about OVF and how it compares with VMDK, refer to VMware's OVF guide.