The only option I see is to use 2 vdip modules. But I also tried these...no luck either. But I guess that you can get them to work. But it will take some time.
If you are using SPI you would need very small files. You need to store the data somewhere because you can only use 1 device on the SPI port at a time. If you want to use a serial interface there will be 1 software serial port, so maximum speed 9600 baud: very slow. You might be able to use 1 on SPI and the other on the hardware serial port though. But then you have to get 2 interfaces working.