I stopped carrying my Leek because the clip couldn't be adjusted so I couldn't carry it like that in my front right pocket. I really like that knife except for the fact that it kept opening in my pocket. That little safety slider thing didn't inspire much confidence.
As to knives that lock closed off hand I can think of the Benchmade mini Barrage, CRKT Lake series and some of the more more mall-ninja s&w knives.