Have you tried Read Write Think (http://www.readwritethink.org/)?

There's the National Writing Project (http://www.nwp.org/cs/public/print/doc/resources/write_read.csp)
http://www.nwp.org/cs/public/print/resource_topic/teaching_reading

OER Commons probably has lots of resources as well (http://www.oercommons.org/). I'd suggest using the advanced search engine, if necessary.

If you google, Reading AND writing projects 4th grade - you'll get a lot of public/private school ones.