Ashy,
I am very flattered that you are so interested in this game, but if I did call someone up it would be one of my alternates. What I can do for you, is I'll put you down as alternate #3 for this campaign, and IF I end up starting a new Eberron game (My D20 modern is off to a rocky start, mainly my fault. If it implodes I'll probably switch to an Eberron game instead.) I'll reserve a spot for you.
I've been toying with the idea of calling up an alternate, but to be honest the game is going well enough I'm hesitant to screw with anything. Perhaps later, but for now the old saying "if it aint broke, don't fix it" is my motto.
Chris