dhkjwhq:
A phone app may work for some people, but it really wouldn't work for my needs.
Your reply seems to be based on lots of assumptions about how the hypothetical smart phone app would behave. I would argue that it's easier to modify the behaviour and appearance of a smartphone app than an Arduino, since the appearance and behaviour of the app are both defined purely in software, whereas the Arduino is a combination of firmware and hardware. Just in case you're not clear about this, I'm proposing that you write an app that does what you want. Make it as pretty and/or flexible as you want. If you just want it to display some coloured dots on the screen pretending to be LEDs, that's all it needs to do. (Personally, I suspect you can do MUCH better than that.)