With Linux, I seem to recall grepping the disk under /dev/ for the contents of the deleted file. It's actually why I still religiously put the name of the file at the top of the file, even though git has kept me from accidentally deleting anything in recent years.
I worry that svn and git have done more harm than good, because I've now got into the habit of using rm -rf (it's the only way to delete .git/.svn) where I used to use rm -r.
