According to many PodCasts / Videos that I've seen of Captain Foley from TrekYards and he and commander cockings have said in the past that the Borg Cube's in Voyager was scaled down to 1,000 meters per side while the original Borg Cube in TNG was 3,000 meters per side. This was to make it so that Voyager wasn't completely tiny in comparison to the Borg Cube. Could it be that there are multiple sizes of Borg Cubes that can be combined together like Combiner Robots in Transformers? Normal Borg Cubes are only 1,000 meters in size and large assimilation cubes are 27x 1,000 meter sided cubes combined into one massive unit? 3x3x3 = 27 cubes? Could the real default cube be ~ 1,000 meters in size and the ones that we encountered in TNG were specialized combined assimilation models?