I, myself, would honestly like to see connected forcefields, A way to link forcefields together via id cards. At the current time I've only seen a max of 64x64 cube, which is well.. only 1/3 of my castle, so I would like to connect 3 together. I mean think about it, if you can use something to connect forcefields together to be seamless, like say a card made at a specific link station or something, and you can link stations together as well using the same method.
Basically, if you had a 128 x 128, you would require 8 area projectors, 1 Link Center, 7 link stations, 7 link cards (All based from main link station), 8 Power Gens, 8 Blank MFFS Cards (for power gen -> area projector), 8 EU Injectors. Doing it this route, the link station would be a projector upgrade so that it connects the projectors, if the projector senses it's forcefield will be created in the boundary of another, it doesn't create the boundary. So the inside of these 8 would be hollow and only the shell would appear.