Manic Panic is semi-permanent. I find it doesn't start fading until it's about time to redye because of regrowth anyway.
^ I'll have to give that a shot. I usually use Herbatint, and though it's supposed to be permanent, it does tend to fade to a reddish hue after a while. Still, I like the fact that I can mix the amount I need, rather than use the whole lot in one go.
I recently tried Herbatint, and found it to be quite good. I used dark brown, not black - but it still covered my regrowth well and didn't burn my head off (practically) as have others I've tried. Good luck finding something though