Purple Sprouting Broccoli
This is the original type of broccoli, an overwintering type that makes delicious sprouts over a long period. Planted in late summer, it makes a huge plant with lots of growth tips, each one of which produces purple broccolini in late winter/early spring. Keep picking and you will get a long harvest, a bit at a time--perfect for lots of meals instead of a glut you have to process at once. Why haven't you seen this in the store? It provides lots of small harvests instead of one big one, so it is not economical for farms. Perfect for the home garden or small-scale grower.
There's a catch: you have to have a mild enough winter that the plants don't freeze out. Zone 7 and up are usually where it is grown. (Can be grown anywhere with enough winter protection.)