it couldn't find anything I had in common with other wallet.dat files....
You couldn't find that wallets are all Berkeley Database files?
$ file foo
foo: Berkeley DB (Btree, version 9, native byte-order)
And that's just doing it manually. Keep in mind that most digital forensics software not only allows searching for specific types of files this way, but also automatic highlighting of files whose contents don't match the extension. You're not fooling anybody.