I looked around a bit to see what might help you.  Appears that files over 4gb are difficult to recover.  Two programs (reported) that seem to be up to the challenge are:

http://www.r-studio.com/

and

http://www.yodot.com/file-recovery/


Make sure you ghost an image before trying out either of these (or other) tools.  Then you can experiment on the copied image.




    Sources: http://windowssecrets.com/forums/showthread.php/137552-Tools-for-undeleting-files-larger-than-4GB
                 http://www.yodot.com/file-recovery/recover-files-more-than-4gb.html
                 http://www.easeus.com/data-recovery/recover-files-larger-than-4gb.html (Another Possible Software Tool)