Is there a way to search with TortoiseSVN (or plain Subversion) for a bit of code that has been removed, and which revision it was removed in? Blame does something similar, but doesn't show removed code.
I just show the SVN log for the file in question, and then choose a revision from some time in the past and see if the removed code is present. If yes, choose another revision half way between the first one that you chose and the latest. Repeat until you get the revision where the lines were removed.
Not scientific, but works for me.