I'm currently building a monk grappler for a high level homebrew game (level 19 now, going to level 30) and this guy is ridiculous, even with a 6 feat dump into grappling (Improved, Greater, Rapid Grappler, Kraken Style, Kraken Throttle, Kraken Wrack)
Speaking of Kraken Style, If you want to be a mean ass grappler, look at those feats, cause (in my opinion) they make grappling one helluva lot more lethal