I get a BindingFailure on a line of code using the XmlSerializer:
XmlSerializer s = new XmlSerializer(typeof(CustomXMLSerializeObject));
According to MS VS 2010 Feedback this is how it was designed. In order to prevent this exception and prevent a slow-down during run-time execution you need to generate a XML Serializer assembly.
There are three tools I could find: Microsoft SGen, XGenPlus and Mvp.Xml.XGen. As of this post, unfortunately, none of these has been updated since 2007.