First, I am going to qualify that I have not created a pk powerhouse in monks (or any class, really). Your monks with the most pks tended to have Baer-tats because it gave them kill-sealing that other paladins don't typically get. I've had Baer's tat, and the people who say that it wasn't that good are really underplaying how powerful pounce is on a class that was not designed with lag in its arsenal.

But since you are much better about obtaining gear than I am, you will love monks. Assuming you cannot summon your victim into a locked room, the recipe for monk melee-based pks is:
1. Curse them.
2. Wear them down.
3. Let the victim lag himself, then immediately respond or intensify. Respond disarms, steals, and breaks even offhand weapons. Stupidly good skill. Intensify is flurry that spaces the damage out over three rounds.
4. If the victim wimpies out, call lightning.

Like all melee-based kills, having large damage output is key--you want to create burst damage when they are in no position to deal with it.

I haven't had much luck with storm monks, but elves, azures, dwarves and humans/halfies are all pretty good, thought they play slightly differently.