I put together a 2' x 4' sign with about 1800 LED's driven with PWM, and these chips worked fine. They're kind of a swiss army knife with a somewhat intimidating 80 page manual (maybe I'm wrong - this is just from memory).
It's not an Arduino driving it, (SBC with an ARM - 9) but an Arduino would probably drive 30 or so chips with no problem. I think I had some contact with TI and they said there was definitely a limit to how many you could daisy chain - the manual suggests 40 I think. I never did establish the exact reason - I think it's clock skew issues with some kind of delays multiplying. Just use a new Arduino pin, and a new chain, for more LED's. You would need a new chip select for each chain too.
Try out the SPI port on the Arduino - that will buy some speed I bet - after wading through the datasheet.
Anyway - the TI chips are not for the faint of heart but if you put some work into figuring them out, they'll work fine.
Paul Badger