Led matrix update

After some troubles the LED matrix I quickly mentioned before is functional. Unfortunately taking pictures of it (without diffuser, I don't have any handy right now) is damn difficult so the photos aren't exactly of  the greatest quality.

The pictures really don't show observed brightness or color very well, so you have to take my word for it: it looks way better live. And unfortunately my DSLR is one model too old to have video capture, so I can't even give you that (and webcams/phone cams are absolutely worthless - been there, tried that, immediately decided to forget about it)

The four matrices in pictures are chained together and driven by Arduino Uno showing simple color cycle where each component is assigned value with simple rotating sin function, so nothing fancy. Nevertheless it looks quite nice for demonstration purposes (well, when observed live, at least). Arduino manages to update the matrix at rate of 300 updates per second, not bad, and code for updating it is very very simple.

My original idea was that this would be easy-to-use (no complex driving logic required like so many matrices do!) and fairly cheap  module for hobbyist use - showing text, smallish graphics ("We're OPEN!") and whatnot, possibly even slide show from SD card (by using some suitable Arduino shield or maybe Raspberry Pi - neither of which I have available right now). Unfortunately the initial small production run costs about twice what I was aiming for so this may be a bit too expensive (around 70€, including VAT). Damn.
 However, extending this to 16x16 matrix should be fairly simple (granted, routing will be a huge pain, even with added board area) and yet change in cost should be minimal, so maybe I just forget this smaller one and go for that instead.

Any ideas or requests, anyone?