The Health Foundation supports MUS projects through their Innovation for Improvement Programme: http://www.health.org.uk/news/twenty-new-innovative-projects-are-selected-improve-quality-health-care-0
NHS Choices offers a general introduction to MUS syndromes / problems.
Information provided by the NHS England "Improving Access to Psychological Therapies" (IAPT) service introduces MUS in a general way and describes NHS "Pathfinder Project" and corresponding evaluation as well as a newly developed Competence Framework.
Guidance from main professional bodies
Medically Unexplained Symptoms (MUS) Project implementation report from March 2011 Documents containing a full report by the NHS Commissioning Support for London introducing a MUS Whole Systems approach.
Practical tips for MUS
Executive Summary for General Practitioners
Economic cost of MUS
NHS Trusts and other organisations with MUS services and projects:
Medically Unexplained Symptoms - a Whole Systems Approach in Plymouth
MUS Long Term Conditions Toolkit
NHNN Team Helps Patients with 'Medically Unexplained' Symptoms
Integrating mental and physical health across primary and secondary care: the MUS pilot project