non-rectangular nvidia

[Marcus Sundman]

Hi,

I've searched the archives, the manuals and the web, but I can't find the  
info I'm looking for. I'm using the nvidia driver and two monitors, A  
(1600x1200 / 113x113 dpi) and B (1280x1024 / 97x97 dpi). I want them to be  
like this:
+-----+
|  A  | NADA
+-----+-----+
  NADA |  B  |
       +-----+
I put option "TwinView" "True" and then I managed to construct a MetaModes  
value like this:
"1600x1200 @1600x1200 +0+0,1280x1024 @1280x1024 +1600+1200"
and this seems to work great, except now it lets the pointer go outside  
the viewports, i.e. to the areas marked "NADA" above. This makes lots of  
things more difficult (edges, corners, Fitt's law, yadda yadda) and I even  
lose track of where the pointer is.
(Other things, such as windows and popup menus, also go outside the  
viewports occasionally, but maybe that's the applications' and/or window  
manager's faults.)

So, how do I make the pointer stay inside the viewports' bounds?
Also, how can I specify the different DPIs of A and B?

Thanks!

- Marcus Sundman