There's a HUGE load of 'em, you're just not looking in the right places. There used to be a large thread on F#itchy before they closed down all of the good stuff, but I saw someone else start one up elsewhere. I'll hunt the link for ya.
edit: found it! You know what to do with the HUMP...
hump://www.pornbb.org/viewtopic.php?t=88363
You'll have to register to see it, though. You might try a one-time mailbox at Mailinator, but you didn't hear it from me.
Alternately, you can surf the Google cache with pornbb.org as the SITE: qualifier, and SUPERHEROINE as the search term.