Mount the disk read only in linux and use photorec to copy all files that are found to another harddisk, and then look for files that have .db extension.
If you find any of those use the file <filename> command to examine the exact file type and if its a Berkeley DB Btree then it's most likely your wallet.
Photorec works on RAW data so it will not restore actual filenames like for example wallet.dat.
In stead it will look at the bytes and try to figure out the filetype from that so it does not matter how many times you formatted the drive if the bytes are still there then you will find it.