The efficacy of a Joe-Job has decreased significantly over the past couple of years. Ever since the Window viruses that starting forging return addresses willy-nilly, we've all been "joe jobbed" for the last few months. Going from 0 to 100 spam bounce messages a day would be much more annoying then going from 20 to 120 spam bounce messages.
Not only that, I have not received a single angry complaint about getting spammed from my address; it seems everybody has learned to ignore the "from" address. (As it turns out I'm effectively immune to the "escalate to the ISP level" attack as well, but nobody's tried that, either.)
I kinda thought it would be more annoying then it has been.
Interesting that those of us on the net now get so much spam that a Joe-job is just another drop in the flood. Mozilla's Bayesian filters are holding against the onslaught, and they aren't even a particularly sophisticated Bayesian filter from what I gather. Apparently for somebody, it's easier to try to (ineffectually) joe-job me then actually read what I wrote.