Hi, HK. Sounds as if your DD is quite accomplished. My kid is a pianist too. Here are some ideas for shorter pieces at about this level, quite melodic (not all are Eastern European, but your DD actually seems to have wide-ranging tastes). The list is, roughly speaking, from more to less difficult. These are from my kid's repertoire, so you're getting HIS teacher's advice indirectly! :-)
Mendelssohn, Hunting Song, Songs Without Words, Op. 19 No. 3
Chopin, Mazurka in B Flat Major, Op. 7 No. 1
Kabalevsky Prelude No. 8, Op. 38
Chopin, Nocturne in E Flat Major (Op. 9 No. 2)
Chopin, Waltz in B Minor, Op. 69 No. 2
Mendelssohn, Venetian Gondola Song, Op. 30 No. 6
Chopin, Prelude in B Minor, Op. 28 No. 6
Chopin, Prelude in C Minor, Op. 28 No. 20
Chamber music: Grieg, Anitra’s Dance from Peer Gynt
Dvorak, Slavonic Dance No. 2 in E Minor
Can I ask what about piano your DD finds boring? I'm not fighting the question -- just the opposite. Solo piano at a high level is really difficult. It takes a long time to learn pieces, and it can be lonely just polishing something for a recital. Piano competitions, in our experience, aren't social or particularly "fun." So I'm wondering (as I do for my own kid) whether joining a piano trio or quintet might be useful -- or accompanying, say, a violinist. My kid has done this in the past but hasn't this year, and I think piano has been less fun as a consequence.
