My dd is almost 8 and speaks German and English. We live in the UK and she goes to school here. She enjoys reading and has recently started to read some German books by herself, maily beginner books (Leselöwen and similar), and has especially enjoyed 'Der Buchstabenfresser'.
We've read Pippi Langstrumpf together and she loved that too!
I was thinking of some of the Cornelia Funke books (as they are orgininally in German) but if anyone has any specific or other recommendations, I'd be really grateful.