A more-form-for-more-content metonymy is a metonymy in which some sort of increase in the amount of form in an utterance, such as vowel lengthening, repetition, or reduplication, is used to stand for some augmentation of the meaning of the utterance.
Here are some examples:
He ran and ran. (The repetition of the verb stands for an increase in the time or distance the person ran).
He's sm-a-a-a-ll. (The vowel lengthening stands for extreme smallness).
