Hello Jamie,
I could not find where it was saying it would support 1920x1080. (column * rows)
Resolution works like you calculate a surface area almost.
The document you linked indicates 1600x1200. So it can manage 1080 rows, but not 1920 wide.
Here is a list of graphics adapters using our technology we have tested which can achieve FullHD at least:
http://www.displaylink.com/products/...&res=1920x1080
Alban