Hi,
At the Christmas lights mini in Sydney last weekend , one of the guys demonstrated a fully functional matrix made up of P10 panels , driven of a BBB (with the Falcon Player) and an octoscroller cape.
Each P10 panel is 32 * 16 pixels and is about $11 US from Ray Wu (indoor panls though ie not waterproof)
He (darylc) had 6 panels together as one matrix
Definitely worth looking at , for text scrolling - he also had movies playing on it (using xlights I am sure).