I've had no luck what so ever getting the latest rawhide driver (the
modesetting one) running on rawhide. I'm running at the moment on a
stretched 1024x768 on my 1440x900 screen.

There's a bug here to track issues with the new driver.
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=198062

One of the X guys was going to be doing some work on it at OLS or
somewhere in the coming week but I can't remember who and can't find
the list post.

I have no problem with it.  Dell GX620 with a 2007WFP ( running at 1680x1050 wide screen with no panning ).

xorg-x11-server-Xorg-1.1.1-5.fc6
xorg-x11-drv-i810-1.6.0-11.20060713modeset.fc6

Couple of things from my config, you need the correct settings for modline and Display.

Mine are : 
DisplaySize  434        272
ModeLine     "1680x1050" 146.2 1680 1784 1960 2240 1050 1053 1059 1089 -hsync +vsync

And "### Comment all HorizSync and VertSync values to use DDC" is something I had to do..
I'm also commenting out glx and DRI but not sure if I have to or not but something in the config was crashing my video card.