One of the great resources we use for multilevel text are from National Geographic school resources. They are called "Theme Sets"--Differentiated Instruction at its Best. Each kit includes 8 copies of 4 books centered around a specific topic, such as Animals in Their Habitats. Although they are written at four different levels, and have different titles, the structure of the books is exactly the same. For example, if you "turn to page 17" in each of the books you will see a map. On page 24, everyone will have a list of "big ideas".
The wording is appropriate to the reading level, but the same concepts are taught. Therefore, you can do some work as whole group then move into small groups based on the reading abilities of the group.
They contain the same quality photos that we see in all Nat Geo materials, and our teachers from grades 3-5 have used them for years. Along with other teachers from my school, they would come highly recommended.
Here's a link to check out. There are about 20 or so kits for Science and Social Studies.
http://ngsptechnology.com/AdvancedSearchResult/tabid/486/Default.aspx
