score:6
The global veg food listing site Happy Cow has a few listings in Frankfurt, including a shop called Best Worscht in Town, which offers both animal-based and Vegan currywurst. You can also investigate the Biometzgerei Spahn, an organic butcher which again offers both animal-based and plant-based products, though it is not quite clear to me if they offer prepared foods or only things to cook at home.