One of my players is playing a universalist wizard with a truckload of item creation feats, and wants to create an item to increase the uses of his Metamagic Mastery ability. We have agreed that +4 levels is a typical ruling for such items (Silversmite Bracers, Monk's Belt, Phylactery of Positive Channeling etc) for 10-16k.
However, these abilities, unlike Metamagic Mastery, are all abilities that you get at lv1. This makes me think it should be more pricey.
Someone got a suggestion for a price?
Not quite, the metamagic rods mimic a feat, with a limiter. And even so, what price range would it be? It is a lv8 ability for a class, and allows complete versatility in what to apply.
Are there any core items that allow you to modify higher level non-passive abilities?