Is it possible for a wizard to create a wondrous item (brooch, belt, whatever, etc.) with 50 charges and a spell trigger instead of use-activated, continuous or command word?
For example, a 3rd level wizard with craft wondrous item makes the following items.
1) Brooch of shield spell (any first level spell cast as if first level)
50 charges
spell level 1 x caster level 1 x 750 GB (page 550, table 15-29 core rule book)
base price: 750 GB
construction cost: 375 GB