I think the banana-chocolate muffin recipe in Joy of Vegan Baking takes like 4 bananas. Since jumbo muffins are the One True Muffin Pan Size (anything smaller is for cupcakes, sorry), the recipe only makes six, so you should double it at least. Muffins freeze ridiculously well, something I learned with delight right after having a baby.
ok, now I need to find one of these jumbo pans.
also, the shrink who did my psych evale for the tubal would find that very funny.