Can FileMonkey create an image dump of disk free-space?
No, FileMonkey can only wipe free-space.
We don't know of any packages that can create a free-space image dump but scanners such as Directory Snoop will allow you to browse and search through free space and recover deleted files.
There are other programs that can re-create all deleted directory and file structures such as PC Inspector and Get Data Back. These will also allow you to recover deleted data.