If the data is important your only option is to use tools like "scalpel" to recover files.
You can only recover small , unfragmented files though.
And with small I mean really small - recovering large files - say 50 Mb or more is highly unlikely.
This means you do not scan for vmdks - but for the files that you stored inside the vmdks.
You could try to download the trial of DiskInternals VMFS recovery but I doubt that it will find the vmdk either