I'm not saying that it can't be done, .. but it's not trivial, and it can't be done automatically (thus my recommendation for a manually editable credits page).
No? Software change such that from a certain point on any edit will automatically update a credit page. At the same time, start running something that goes through all the non-deleted edits and update the page as well. Then and only then do one display a link to the credit page. The speed of any program that go through the history of all the articles can be adjusted to run over several weeks / months at a rate the server can cope with. No one is seriously (I hope) suggesting that any change will need to be made overnight.
(One will need to take into consideration what happens when pages that was deleted when the program did its run are then undeleted after the credit page goes live.)
KTC