Today VMware released a new Technical White Paper about stretched cluster in combination with SRM. The document is about 18 pages full on information on the technology you can use to achieve this and understanding the options and goals. It also contains some sample scenarios and solutions on which you can base your upcoming setup.
You can download it here.
“This paper is intended to clarify concepts involved with choosing solutions for vSphere site availability, and to help understand the use cases for availability solutions for the virtualized infrastructure.
Specific guidance is given around the intended use of DR solutions like VMware vCenter Site Recovery Manager and contrasted with the intended use of geographically stretched clusters spanning multiple datacenters.
While both solutions excel at their primary use case, their strengths lie in different areas which are explored within.”