I think the MXN-2 screens use an IDE for their FDM, not SATA. So you can get IDE FDMs, just google IDE 32GB FDM and you will find them. The problem here is that you need to find one that is at right angles, so that you can insert it without sticking out. Also, I am not sure about the Windows OS, because the Samsung screens will not execute their player software unless it is an image from Samsung. So if you do purchase this large FDM, you will need to do so re-partitioning on them. This is all a laborious work.
You can insert a USB memory stick on the USB ports of course and configure the client to look for that E: drive for data - I guess this is a bit slow. It is just a suggestion.
Bill