My son, who is 8 years old, has Bipolar ODD and ADHD. I'm finding it impossible to find a doctor willing to take him on because of the multiple diagnoses which he received after being committed to a children's hospital psych ward. Can you make any reco

There R doc who will. There are many doctors that manage these complex children. Usually they are subspecialists in pediatric psychiatry or developmental pediatrics. They usually work within a team approach with counselors, therapists and tutors to cover all areas of disability. Check with your nearest children's hospital.
Team approach. A patient who presents, with a complex mental health history requires a team approach, not one professional will be able to make an impact on his/her care.A thorough evaluation , physical exam, and family, social, mental health history is a start.Medication, behavioral intervention, parent skill training and close monitoring of clinical response a must.Clinical psychology and child psych is a good combo.
Talk with others. I would recommend talking with the hospital that he was admitted to and see if they have any recommendations for a pediatrician. You could also call around to different pediatric offices and find out if they are taking new patients. With his multiple diagnoses, i would also recommend that he follow-up with a child psychiatrist.
Try Academy. We have an organization for all of the child psychiatrists called the american academy of child and adolescent psychiatry. They have a section on their website to help find a doctor. Check out: www.Aacap.Org. Good luck.