That happened a number of times in the later 70's when the Flyers, Bruins, and Habs were consistently racking up 50+ wins and meeting each other in the final or semi-final. You can even throw Buffalo into that the mix as well, they were usually good for 45+ wins. Montreal (59) and Boston (51) met in the 1978 Final, their combined 110 wins is the highest combined total I've come across.
More recently, the 1996 Red Wings (62) and Avalanche (47) combined for 109 wins. In the 2001 Final, Colorado (52) and New Jersey (48) combined for 100 wins, and I think that was the last time it happened before the shootout was implimented. Now that every game yields a winner, this has become more common. In 2006 Buffalo and their 52 wins played both Ottawa and Carolina, who also both had 52. It even nearly happened in the first round between Detroit (58) and Edmonton (41), a 99-win combo.