Cooked cabbage freezes just fine. The only problem is with the texture change with raw cabbage - it will never crisp up again, but if your going to cook it that wouldn't make much of a difference usually. But then again, raw cabbage should be blanched and shocked before freezing - so it wouldn't have the raw crispness anyway.
And I just LOVE cabbage rolls!
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain