SRS Document and Architecture Specialist

We are looking for a Company or Individual to create a Sotware Requirement Specification Document (SRS) for a Social Networking Website in order to present to a programming team for quotes. The applicant must be proficient in LAMP technologies and have previous SRS and software architecture experience. There is an existing "beta" web site on which to base the document on but we are looking expand on this and therefore we are looking to work with someone who has proven expeience in development and web application design who can ensure that the document is produced accurately and clearly covering all bases including database structure, security and modulaed development Examples of previous work (confidential elements can be removed) would be an advantage.