OK, weird idea time. I'm not particularly interested in making the effort to create a costume for a convention; if nothing else it would get in the way of my wandering as people ask for pictures and so on.
However, I did have an idea that I thought would be interesting: Create a couple of t-shirts that had character logos as they appear on the costume. The classic examples would be Superman and Batman; you see t-shirts with their logos all the time, but the shirts also recreate how the character's chest area would look in costume. I was going to get a couple shirts made like that, only with characters that aren't popular enough that anybody has ever bothered selling shirts like that. My first idea was Ultra Boy from the Legion of Super-Heroes; since I'm a legion fan and his logo adapts well to that sort of shirt.
If I'm going to bother to go ahead and get shirts like this done, I would also like to make one or two based on older characters, preferably PD but that's not mandatory. Any suggestions on characters who have that sort of chest logo that could work on a t-shirt, who are NOT popular enough that somebody's actually already done it? The first one that comes to mind is Black Terror, but too many people would think it's the Punisher, and they're a bit too well-know.