As others have stated it seems there are a ton of pieces on the pml 4/5 with a great piano part. Specifically from my experience teaching a high school second band and occasionally helping with the top band, here are pieces that we've done that fit the bill

Grade 4-

Khan by Giroux
Seal Lullaby by Whitacre


Grade 5-

Danzon no. 2 by Marquez

Children's March by Grainger (grade 4? can't remember)

Aurora Awakes by Mackey