The one I had recently that I'm really thinking might make a good story is a Flowerpot friendship story starting in the 4th year and leads to the summer between 4th and 5th years where Harry is visiting Fleur in France.
The Voldemort stuff will be handled quickly by the adults so it's not an issue.
Basically the plot will be Fleur trying to set Harry up with (an age appropriate) Gabby.