The two professional data recovery companies didn't fail without a reason.
You could create a copy of the disk using 'dd' and parse the created file for certain known filetypes (based on specific file headers or tail information) but this is extremely painfull and takes a lot time. If you want to get back images or fonts, then it could work. To retrieve textfiles you will have to read your way through the dd file. For complex binary files like office documents it will be a horrible task. You could write a few programs to parse the contents based on what you are looking for, if the value of the contents is worth the effort. I don't think that there is any existing single application that does it all, just the way you want it to be.
Sharing home directories is not a good idea, as it seems.