tri color LEDs ... with different animations and modes

assuming we are talking about more than, say 8*100 LEDs

1) you will find out your first code is too slow.
2) you will find out that multiplexing is out of the question.
3) your first color modulation scheme will fail.
4) with a lot of determination and a 100MHz Cygnal and/or a CPLD you may eventually succeed.

a couple of tips
you need to refresh your sign at least every 8 ms or a 'shimmer' is going to be visible.

Unless you make every led (3 per chip) individually programmed for intensity you will need to use a PCA equipped uC or a CPLD.

Scroll will be the killer

Make sure you use load and latch for your LEDs such as a ST2221a

You will want to sense ambient light and regulate your brightness.

been there, done that

Erik