Re: Workshop!
BayCon (http://baycon.org/2008/index.html) is the Bay Area's largest SF convention; it's literary rather than media, but it's big enough to have a bit of everything. No way could a panel get in now, though; it's scheduled months in advance. I haven't attended BayCon in a few years, though.
PantheaCon is the only one I've attended recently, and it's pagan-themed, not fannish. There's potentially use for a copyight panel in that, but the focus & issues would be different from fandom's concerns.
Escapade would be a great venue for it, especially with the option of a 3-part discussion: day one, defining terms, history of copyright & what that means; day two, cases relevant to fandom & current trends in law; day three, what's next, tech issues, how do we change the parts we don't like & keep the parts we do.
That makes for days 1 & 2 having the option of handouts, including extras to go to people who didn't attend, and day 3 being meta to go home & chew on.