Recently I added an arrangement of Dvorak's Carnival Overture. This piece does not readily spring to mind as laying well for solo string and piano, but I had a student who loved this piece and yearned to play the "good" parts on the viola. I let it percolate for several years, but it is now available for every violist wanting to play the all the best parts. It is and was one of my favorite orchestral pieces to play - I hope you enjoy this!
Here is a link to the Carnival Overture.