For basic triple doubles (i.e. 10+,10+,10+) the 50 point game is far more rare.

http://www.basketball-reference.com/...ts#stats::none
That said, in the modern era at least, LeBron type 25+,10+,10+ triple doubles are pretty rare. 27 since '86 (when Bkb-Ref started counting) by 14 different players:

6: LeBron

3: Magic

2: Barkley, Bird, Baron Davis, Jordan, Payton, Rondo.

1: Steve Nash, Chris Paul, Paul Pierce, Ralph Sampson, Isiah Thomas, James Worthy

http://www.basketball-reference.com/...=pts#stats::28
There have been only 19 playoff 50 point games in that span, 8 from Jordan, 3 from Iverson and no one else more than once.

http://www.basketball-reference.com/...ts#stats:: 28