There are new 64 LED serial boards at http://moderndevice.com
The page shows photos of the prototypes but the boards are at fab now.
They use a 16 LED through-hole driver chip (STP16C596) are not multiplexed, and hence are really bright.
The interface is a standard SPI but there is also a blanking line that could be used (I believe) for things like an LED strobe light or PWMing the whole panel.
Paul