DocShare illustrates the CQRS pattern on Windows Azure and also uses MVC4 Web API. DocShare uses two web roles, one for queries (reads) and one for command (writes). Each has a UI and a Web API service.
For a full description, see the following article on David Pallmann's bloghttp://davidpallmann.blogspot.com/2012/04/docshare-illustrating-cqrs-pattern-with.html
Implemented as two Windows Azure worker roles, DocShare's query (read) and command (write) implementations can be scaled separately. The write implementation uses blob storage; the read implementation also makes use of the Windows Azure CDN.
DocShare is a community donation of Neudesic.