*pulls out Sonatina album that everyone within a 15 mile radius of me has because we all go to the same cluster of teachers*
Well, it looks like Clementi and Kuhlau are the big ones. Beethoven has one in G major-I think this is the one composed when he was quite young.
Diabelli also wrote one in G major, but its first movement bored me terribly. I think that's why my teacher never made me do the 2nd and 3rd. They do look more interesting, actually-the second movement is a Scherzo and has lots of hand crossing and the third movement is a Rondo. Funny-the first movement is Andantino Cantabile while the others are allegro and allegretto.
*flips*
Ah-Jan Ladislav Dussek composed a sonatina (guess the key..) in G major that I'm rather fond of. It has only two movements-an allegro that's kind of bland in the left hand but has a lyrical melody and a Rondo that's equally "charming." [Quotes are there because I think charming is a very empty, meaningless word to describe music, but I used it because I couldn't think of a better word.]
Le Squinch
P.S. I've no clue about their grades. They're all around the Clementi range, though.