Here is a link that has some good ideas and resources for Thematic Units. Integrated Unit Instruction is a research based approach to learning that allows teachers to integrate instructional standards, functional skills, and IEP goals/objectives into meaningful units of instruction instead of isolated skill activities.
http://www.4gaslps.com/ThemeUnit_page.html
More information on integrated unit instruction can be found at these archived pages:
http://pickettsmill.typepad.com/pritchard/2008/11/forms-for-unit.html
http://pickettsmill.typepad.com/pritchard/2009/04/unit-plans-continued.html
http://pickettsmill.typepad.com/pritchard/2009/04/unit-plans-from-february-inservice-part-1.html