Erica Durance is now on the cancellation list for Dragon Con in Atlanta but Michael Rosenbaum, James Marsters and Tahmoh Penniket as well as Aaron Douglas and Robert Picardo who have all appeared on Smallville are confirmed as of right now for the biggest Comic Convention in the southern U.S.
http://osck.wordpress.com/2008/08/13/michael-rosenbaum-confirmed-for-dragon-con-erica-on-the-cancellation-list/
Photos here http://www.theuniquegeek.com/2008/08/14/dragoncon-countdown-in-pictures-14-days-panels-panels-and-more-panels