I have a glut of home-grown cabbage at the moment, more than I can eat before it goes bad! Is there any way to freeze cabbage (raw, cooked, whole, shredded...) or would I have to make gallons of cabbage soup / pickled cabbage?
Depends on the type of cabbage, but I've had success with prepping as if I was about to boil, and then freeze on a dry cloth; Once frozen, transfer to an air tight freezer bag, and use as fast as is practical.
I've never had particularly good experiences with freezing cabbage so that it's usable as a "fresh" vegetable afterwards. Personally I'd recommend going down the cabbage soup / picked cabbage route, I'm afraid.
I have frozen fresh, chopped cabbage with success. I halved the head, cored, and cut into strips. Make sure it is dry and seal in a freezer bag, squeezing out the excess air. I would then add it to pastas and soups, never noticed a problem with taste or texture.
Try food.com or just google freezer coleslaw. It is crunchy and tastes almost as good as fresh. Try a little freeze overnight and taste, if you like it, freeze lots. It is handy to have for a quick salad.