This sounds like the sort of rustic food I adore. I have bags of assorted beans in the freezer, runners (the actual bean), borlotti, corona d'oro, annelino giallo. This produces an interesting blend of colours, sizes and textures, since some of the beans are very nutty, others are soft and tend to collapse.
I look forward to the recipe.
Derek :)
PS The borlotti, a climber, are worth growing if only for the attractive coloured pods ...