Yes, it looks like we have licked this thing for now. I have battled comment-spamming slime for months now, and thanks to the installation of a few good Movable Type plugins, it appears all is good now (she types with fingers crossed, which is even tougher to do than you may imagine).
At any rate, I must give credit where it is due. Six Apart, which is still not one of my favorite companies, has put a great deal of effort into providing or leading site owners to items to help stem the comment-spam tsunami, and I thank them heartily. Gratitude also goes to the developers. As I don’t wish to tip my hand to the spamming losers, I won’t specify what methods I am using, but to the developers, you rock.
Perhaps now I can get some sleep.
Thanks, too, to commenters. You have the patience of saints and I love you for it.