I did a quick sanity check. I have an ATtiny84 with CKOUT (aka CLKO) connected to the TLC5940 GSCLK pin. Everything else is connected an Uno. No problems.
8 MHz, 4096 steps, that comes out to 512 microseconds. I wonder how well blink-without-delay would work? Is it really that important for BLANK to be fired accurately?
@fungus, what did you build with an ATtiny84 and a TLC5940? How accurate does BLANK need to be?