I also can't get X to work with a Dell Optiplex GX270 (i865G), (xfree86_4.3.0-pre1v4 _did_ work). I just tried xserver-xfree86-dbg, and it fails with:
(II) I810(0): Display Info: DFP2 (second digital flat panel): attached: FALSE, present: FALSE, size: (0,0) (II) I810(0): Currently active displays on Pipe A: (II) I810(0): CRT (EE) I810(0): Cannot shmat() low memory Fatal server error: Caught signal 11. Server aborting please let me know, if (and how) I can provide more Info. - Christian