Xrandr and Nouveau

[Harry Putnam]

Setup:
Running Debian wheezy 3.0.0-1-686-pae
xorg: # aptitude versions xorg
        ihA 1:7.6+8  
Currently have Kde and fluxbox desktop pkgs installed and in use.
-------        ---------       ---=---       ---------      --------

[Note there are many drivers installed, apparently from the initial
install.  But I'm sure most are not really doing anything.  I can see
Nouveau being loaded in Xorg.0.log which I will provide at the end.]

Sorry if this ground has been well covered already, but I saw nothing
of recent vintage about it.

I like a big sloppy panning desktop.

I recently switch OS from Gentoo to debian, and have not been able to
get a large panning desktop setup.

The debian install left with Nouveau being loaded during X session
building. There is no xorg.conf employed (by default).

I've tried to insert some part of my old xorg.conf but unsuccessfully
so far.

That part really just comes down to one line that sets a `Virtual'
size.

   Virtual     2048 1536

I can start X with that in xorg.conf but I do not see the result I
learned to expect when running Gentoo and `nv' driver.  That is a
large panning desktop.

Since that seemed not to be working I thought to try with Xrandr.
But I found that commands like:

 xrandr --output DVI-I-1  --mode 1440x900 --panning 1680x1050

Appear to grow the screen real estate quite dramatically, as judged by
a portrait image I use for background, growing quite noticeably and
the panel KDE had at the bottom of my viewing area is moved down out
of site.

Apps that happen to be running are shifted to the right several inches
it appears.

But the mouse cannot pan out into the larger size.  It appears to
still honor the original screen borders. 

Am I hitting a bug? 
Is it possible that some conflict between nouveau and xrandr is what
I'm seeing?