The address space devoted to the PCMCIA slot on the A1200 is about 4 megabytes, therefore the maximum addressable ROM cartridge that could be used on an A1200 is 4 megibytes x 8 bits per byte=32 megabits.
Also, scaling, rotation, and alpha blending are OpenGL functions that will be added to the SuperAGA chipset in the Natami when it comes out.