Just a quick note to point to another website from a different gaming convention. On the gameholecon.com website, they have a spreadsheet that shows up when you are looking at registering for events. I find it rather nifty that I can see what I've already signed up for (before and after buying the tickets, it shows the wishlist too!).
Please take a moment to look at their site and consider this as a possible add to the registration process for GenCon.