I've recently been arranging pieces from Bach's Notebook of Anna Magdalena Bach for guitar duet. Originally written for keyboard, Bach gathered them together into two books in the 1720s and presented them to his wife, Anna Magdalena. They make great easy duets - as well as giving us a feel for domestic musical life in the 18th century. In the "Aria" I have simplified the rhythm slightly in one or two places.
I wrote these pieces with players in mind who could play Grade 1 pieces confidently and were looking for something harder. My favourite is the second one, Dreaming of the Sea. Pupils seem to like it best, too. The opening of the third, White Horses, is a good opportunity to get to grips with playing in second position.