I don’t see any straightforward way to do this with the same basic architecture, if it has to work with two-pin LEDs. There are, of course, ways to do it, but it would require a very different design, since both the row and column drivers assume that one side is high, and one is low.
If we were to build a Peggy variant that took discrete bicolor LEDs, we would design it so that it took common-anode 3-pin bicolor LEDs. That would be a very straightforward modification.
