I'm trying to figure out a way to up the range of locate object to a few hundred miles. Discern location is beyond me. Crystal balls and cauldrons of seeing only say they work with scrying and scrying only works on creatures. Is there a wonderous item that could do what I'm trying to accomplish through locate object?
Sadly, there's a big hole in the scrying subschool's abilities where spying on objects is concerned. The spell obscure object seems to suggest that there are scrying spells that can view objects directly, but I've yet to find any.
Indirectly, scrying can view objects if they are on or near the target creature, as can arcane eye and others. Of those, scrying is your best bet given the range requirement. If the object is unattended, or you don't know who has it, you're pretty much out of luck.