It was a while ago, but there was a discussion about multiple Columbo actors in the same episode of other shows. http://pub10.bravenet.com/forum/static/show.php?usernum=806565873&frmid=6&msgid=1393052&cmd=show What episode of Columbo was Agnes Moorehead in?
Technically maybe 50-60 episodes, but actually she was in the stage play that toured in 1962, so daily performances of that. P.S. I could not get to anything with that link you added.
Got it! http://pub10.bravenet.com/forum/static/show.php?usernum=806565873&frmid=6&msgid=1393052&cmd=show