As a former SC resident, I can contribute some help (maybe)!
First, for those of you college aged, the College of Charleston and the University of North Carolina both have large(ish) and very active anime clubs. For the younger of you, I don't know how they would take it if you somehow showed up, but it's possible you could contact the clubs and see if they have any tips or encouragement for you to network in your high school/middle school or something. The major advantage of this is that in a club you can easily get large groups together to make it to cons under a group rate. Well, besides not feeling totally alone in your cosplaying euphoria.
At USC, the anime club (Club NASHI) has been hosting a small convention on campus for the last four years or so. The highest attendance is only around 1000, but this is still a local con and if you live nearby you should go show support! This year's con is already over, but if you want to see them, go here: http://web.sa.sc.edu/clubnashi/index.php
CofC's anime club has a Facebook, here: http://www.facebook.com/group.php?gid=114437551947759
There isn't much overt activity in the MB area, but those of you at CCU might want to consider making your own campus-endorsed club. Try contacting other clubs to see how they got started, but being an officer and/or founding member looks great on transcripts and whatnot. Still in this area, there is a costume shop called Imaginations (it's also a dancewear store) where you can get a ton of cosplay-related things including wigs, prosthetics, theatrical makeup, bodysuits, props, etc. Their site is here: http://www.imaginationscostumes.com/
I imagine that other cosplayers go here when not blending in.
I am personally no longer a local (moved north!) but I hope that all the research I did when I was can help you all! Best of luck, and you're not as scarce as you think!