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 blog
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.