I have truned my CHIMIE 22inch monitor to portrait. the image is quite crisp, but there are unusal visual effects probaboly best described as glare.
According to Wikipedia this may be due to the poarisation of light optimised for landscape mode.
According to other posts the "TN" flat screens (Twisted Nematic type) are not as good (unsubstantiated comment) and that the Dell Ultrasharp is not TN and gives better results
My 26 inch Samsung has a rotate pivot - I will try that next to see if the same visual effects are present
So I saw a picture of Bill Gates computer, a 30" Dell with 2 widescreen monitors in portrait on each side, and I tried to do this myself. I already have 2 x 22" so I got a 30" Dell. Problem is, when I turn the 22" in portrait mode and turn the monitor on its side using the Nvidia control panel, the text isn't quite as crisp, you really have to look up close its not obvious but its there. I tried on another system using an 8800GS and same story. Thing is, I can't find a single thing on this phenomena anywhere on the web so I'm hoping someone can let me know whats going on here.