These 2-pin red/green guys are also charlieplexable. This requires only I/O pins and resistors.
60 R/G devices, being 120 LEDs, would require 12 I/O pins (30 R/G device, being 60 LEDs would require 9 I/O pins).
This solution wouldn't be so hot for an "all pixels on" situation, but the LEDs mentioned aren't, in my opinion, well-suited to some ultimate signboard ideal.