Hi Jenn,
First thing I want to say is that the NVIDIA driver (the blob version) from nVidia download site, does not properly support RandR yet. I am not sure to what
extent exactly, does it support or NOT support RandR, but it is definitely not perfect. It is said that it eventually will have RandR support, but when? Who knows..
Since it does not support RandR (properly at least), there's a decent chance that you will need to configure your xorg.conf file to do the work for you (set up your display), and restart X for the new layout to work, rather than being able to dynamically rotate your monitor and rotate it back again from your desktop. What does this mean for you? One of the following, probably:
1) You will use your portrait layout
all the time, OR..
2) You have two separate xorg.conf files, one for landscape (normal) and one for portrait, OR...
3) You use multiple "ServerLayout" sections in your xorg.conf, and when you start X, you specify which layout to use.
In your case, it sounds like you are working with only one monitor? That may make the situation a little easier to configure, than a multi-monitor setup.
Anyhow, before I ramble on any further, allow me to suggest you read this page here, and check out any links included within the text on that page; it appears to be a really concise little tutorial/article about rotating ONE of two monitors, however the principles applied to the rotated monitor in this article, should apply equally well to a single monitor setup like yours (except you should probably not need the Xinerama extension). Here's the page:
http://zuttobenkyou.wordpress.com/20...al-head-setup/
To close: I have dual rotating monitors, dual nvidia cards, and am using the nVidia driver also on my own system. I'm also using *similar* versions of the Xorg packages mentioned in the article. So, if you try some experimenting based on that article, and still cannot achieve what you want, I would be willing to try the same stuff on my own system, and see if I can get it to work. Just ask, and I'll give it a shot. If I get a working solution, I'll post the details for you.
Best of luck,
Sasha