Was also going to suggest Panzanella for the sourdough - yummy!
The Italians use stale bread up in lots of soups too - like Tuscan Layered Bean and Bread Soup (a bit minestrone-ish) there is also one with lots of different cabbage leaves and bread. Doesn't sound all that appetising, but it is delicious.
Also, Bread and Onion Salad:
half a loaf of 'sturdy' bread (rustic, artisan)
1 small red onion, finely chopped
handful of basil leaves, roughly torn, plus extra for garnish
2 beef tomatoes, roughly chopped
3-5 tablespoons red or white wine vinegar
5-7 tablespoons extra virgin olive oil
Salt and freshly-ground black pepper.
Break bread into chunks and soak in water for 10-15 mins.
Mix chopped veggies and basil in a large bowl with the vinegar and oil and season to taste. The amount of oil and vinegar needed will depend upon the absorbency of the bread - you have to gauge it! Squeeze the water from the bread so that it is moist and "bouncy", combine with the remaining ingredients (be gentle, otherwise the bread will break up too much). Adjust seasonings, vinegar and oil as necessary.
You can add radishes, celery, spring onions, or whatever takes your fancy at this stage (optional)
Bread and butter pudding? (No, not savoury, I know, but still nice)! Maybe your bread is a bit too hard for that.
PS - If you don't freeze your breadcrumbs, they will go mouldy very quickly!