For those who may be interested: Google Books has some verse composition textbooks available for free (Latin and Greek).
J.A. Lupton’s Latin Elegiac Verse Composition
A. Sidgwick’s Greek Verse Composition
B.W. Beatson’s Greek Iambic Verse
H. Kynaston’s Greek Iambic Verse
I know someone who has used at least the first two in class with great success.