ok, im not going to go through all the Prestige Enhancements Item Sets .and their +\- only 1 thing that sticks up.
monks look to this set as their alternative green steel items( since wraps can't be crafted in the green way.)
there are so far 3 sets for the 3(?) monk PrC .one for the Shintao Monk, one for Ninja spys and the last for the (coming) Henshin mystics.
the main power ( not the power that every one forge for himself.or the ability bonus,which they all have about the same) of each set is placed on the set's necklaces. let's see what each of them get.
Shinto monk : Concentration +15, a very viable power. needed by all monks and normally take up a needed slot. not anymore for these guys.
Henshin mystic : +1 to ki on hit. make it even better then the +15 the shinto get since it add the current ki power, not it's max.
Ninja spy : the power to cast invisibility 3 times per rest for 15 min duration.(cast at 15th level)
first off. i don't know any monk who can really stay invisible for 1 min. let alone 15. too many things to hit. or even the odd breakable item.
2nd .the ninja spy get at level 6 an ability (cost 15 ki, last 1 min. in fire stance i can go whole quests with this effect on.not to mention ninja spy gain ki while hiding.so even not on fire stance 15 ki can be gain very easily) that not only turn him invisible, but for the reminder of it's duration also give a 50% miss chance for being insubstantial(like a ghost. true sight doesn't help against it).
so what does my super rare item that is built to name my PrC give me? 3 time per rest the chance to do what i already can do. and i know. i can just take the shinto\henshin set. but it just feel wrong to call yourself one thing and being forced to take an other class items, cause your's just don't cut it the same way.
what can you have instead of the current power? i can throw a bunch of stuff not too powerful but nice enough for ninja spy to pick this set instead. for example:
-make the item double the duration of the normal Ninja spy shade form.( from 1 min to 2 min)
-increase his sneak attack dice by 1d6 more
-increase his movement speed,( if u think too powerful,then only while hiding. like his PrC II ability)
-give him the hide in plain sight ability (like a ranger. hiding is considered 2 eyes better)
-let him cast knock 3/rest at 15th level (also a 2nd level spell like invisibility, but one i'm sure a lot of ninja spys would love)
i can go on, and so can any of the other readers. a lot of things are more useful then what was given so far.