Xinerama and workspaces

[James Birkett <james birkett co uk>]

I have just set up a second monitor on my system, and like the way
Xinerama allows you to move windows between screens. On the other hand,
it would be very nice to have workspaces treated separately on the two
screens - for example, if I have a dvd playing on one monitor, I would
like to be able to use the other monitor independently, in particular
switching workspaces. Is there any way of doing this? 
If not, would it be possible to make the pager Xinerama aware, so that
it can put different workspaces on different monitors?

(Using X without Xinerama would work of course, but moving windows
between screens then becomes impossible.)

Thanks in advance,

James Birkett