Moving windows between monitors w/o xinerama

[Chris Hoffman <bosshoff gmail com>]

Dear Sirs,
  I have recently installed Ubuntu, which comes with the Gnome
desktop.  As I don't want to make ripples in the water just yet with
my configuration, I decided to make it work the way I want it to.  So,
the first thing I did was to add dual-monitor support in the form of
the proprietary fglrx ati driver.
  All is working fine, except that I am dissatisfied with the "two
monitors, two drivers" concept.  Basically, I like the ability to
maximize windows to their own partition, but would like the same
features of xinerama otherwise.  For example, I do a lot of image
editing with the GIMP, and I am currently unable to put all of the
tools windows on one monitor while having the image on the other.  Are
there any ways of getting this functionality?
  Keep in mind that, when moving GIMP windows, these windows must
still remain in communication with each other; that is, each window is
just a part of a whole, so the interoperability must be maintained. 
Thanks.