The desktop setup was just an example, and you're right that we could rotate any screen, as long as the horizontal resolution (vertical resolution at 0 degrees) is at least 1024.

In the laptop world (per the article), it's difficult to do portrait orientation and still type. :)

Ever viewed one from more than 15 degrees off-axis? It starts looking strange really quickly.

(I realise these guys would get the same problem with the 3:4 arrangement, but let this at least be a warning to anybody eyeing up a potential vertical 16:9 setup.)