It seems like this topic comes up every year or two. There are a lot of opinions of what would look good, and some people who only like black. And of course, there was the dark blue ProgPower XI shirt, and the dark green ProgPower XIII shirt (did those not sell as well?). I personally would be into a dark red shirt. But considering past comments, it kinda seems like people who only like black might avoid a shirt of any other color, whereas most people who would like another color won't skip a black one just because it's black.
I understand doing a general run of more than one color may also not be cost effective, but I wonder... with the online companies that now offer custom shirts with a variety of designs, with the customer's choice of shirt color, I wonder if it would be possible to offer more color options for only those who pre-order and are willing to spend the extra money?
Whatever... just a thought. I actually think black is generally the best color for this type of shirt... the only issue being that metal fans often have so many black shirts that some variety can be nice at times!