Wondering what the OP's source was, because as others have already stated it's been done many times.
Here's a few people I've verified have had these performances recently:
Rondo (5/9/10) 29/18/13 (pts/rbs/assists)
Rondo (4/20/09) 19/16/12 (pts/assists/rbs)
LeBron (5/13/10) 27/19/10 (pts/rbs/assists)
LeBron (4/21/11) 24/15/6 (pts/rbs/assists)
LeBron (5/13/12) 32/15/5 (pts/rbs/assists)
LeBron (5/20/12) 40/18/9 (pts/rbs/assists)
LeBron (6/7/12) 45/15/5 (pts/rbs/assists)
Chris Webber(5/09/02) 31/15/5 (pts/rbs/assists)
Carmelo (4/19/11) 42/17/6 (pts/rbs/assists)
Duncan(4/19/08) 40/15/5 (pts/rbs/assists)
Duncan (5/29/08) 19/15/10 (pts/rbs/assists)
Then when I was looking at Duncan, I realized back in 2003 he averaged 24.7/15.4/5.3 over his 24 playoff games that year, so he did it many times that postseason alone. Then I got tired of researching this stat.
