The Tor developers were eager a few years ago to talk with people who were blocking Tor to see if they could help find alternatives. I realize you've probably thought about this a lot already, but have you ever discussed it with them? Alternatively, do you think you could explain more about the kinds of abuse that are typical when people sign up over Tor?

I realize that might come across as naive, because it's not as though they somehow know more about your abuse problems than you do, and it's also unlikely that they know something obscure about Tor that would turn out to be surprising and important for you. But they're certainly motivated to see if they can help people think of alternatives.

(I'm not actively involved with Tor right now, but I've been pretty close to the project in the past.)