After some discussion, I’ve decided to put it back up, for now, but I’ve reduced the checking frequency from twice a minute to once, and I’m only getting headers rather than the entire blogspot page. I’m going to close up the source again also, because it really could become a problem if lots of bloggers start doing the same thing.
I think that if this really shows up as significant traffic at Pyra, they’ll figure out which IP to block. But as Steven Den Beste says, they have hundreds of thousands of sites, and get millions of hits per hour. I suspect that right now it’s just spitting in a hurricane in terms of bandwidth.