I baked an olive levain today.
This was basically like Hamelman's Olive Levain: 10% whole wheat, no yeast, just starter. I loved it:
Delicious, but not cheap (well, at least by bread baking standards). The olives alone cost as much as... what... thirty pounds of flour and a pound of salt. I can bake an awful lot of regular sourdough bread for that much money. Yes, ok, to put it in perspective it is still cheaper than a drinkable bottle of wine, but still... baking bread, one gets spoiled by how inexpensive a hobby it is.