I wasn't familiar with the retina z2, had to research it.
Anyone else have RTG recommendations for an A2000?
A Picasso4 works in a 2000 and is real nice but the board has to be broken and it's a real expensive option. I think the best value gfx card for a 2000 is the Cybervision64/3D. It doesn't have pass through but it is faster and has more bandwidth than everything but the Picasso4. It also has 4MB of VMEM and supports 3D (more usable with a slow gfx bus). A dual input monitor (my favorite), 2 monitors or a monitor switch isn't too much of a hassle after getting used to it.