After reading thier description, I gathered that they used every single bit of bandwidth that their radios could consume, and then ran as many radios side-by-side as they could, and then doubled that using both H and V polarization....
So I imagined, using the newly claimed 108mbps/per channel MIMO technology, you could get about 1.2Gbps using a radio on each of the 11 channels in B mode, and if the technology applied to A mode, another 13 channels for 1.4Gbps(I'm reaching here...

) for a total of 2.6Gbps. Double the radios to utilize both horizontal and verical polarizations, and that would provide 5.2Gbps of data, using only(all of?) the publicly available spectrum.
Of course, most of this is really a stretch of the imagination, and probably wouldn't even fit in the bandwidth as I described, but it is a funny thought... If you could bond enough wireless links, you could achieve any data rate you wanted...
Hitek