I'd like Pmorph Any Object, but there's some contention...so here's my proposal.
How about we make a customized version of Polymorph Any Object, that has some code changes to make it specific to your campaign's rules? We'll remove it's ability to affect creatures and remove the spells that can target creatures from its list of spells it can emulate.
We can then, to keep it 8th level, perhaps consider some increased ability when affecting objects. For example, perhaps we allow some utility to transmute objects into valuable materials, with limits? Here are some possibilities:
Transmutation Without A Circle: Using Pmorph Any Object to change objects into valuable materials invokes a law of equivalent exchange; gold piece value cannot be spontaneously created, but it can be altered. To change a sword into adamantine, one would have to use a normal sword AND other materials that equal the value of an adamantine sword. This would make the spell the equivalent of a 'portable shop' for any object that doesn't involve magic and enchantment...which at these levels is most of them, really. Cold Iron would still be off limits, since it's not the material that makes that unique, but rather the manner by which it is harvested and processed.
No Cheating! Well, maybe a little: Transmuting an object into a substantially more valuable object reduces the duration factor, and prohibits permanence. I'd suggest using the rules for Major Creation as a good guideline. A spellcraft check of fairly easy DC allow someone to spot 'faked' valuables, meaning that it can't be used to defraud a canny merchant. Further, using the spell to attempt fraud would be a criminal and unlawful act.
Simplify, simplify, simplify: No new special rules. Rather, we simply add a few spells to the list of spells that can be emulated to replace the ones lost. Major Creation, Fabricate, and perhaps something like Wall of Stone or similar "change stuff into other configuration" type spells would be under consideration.
And if none of these ideas appeal, I'll just take Horrid Wilting. Maybe reskin it as something less gruesome though.![]()
Fair warning in a couple posts he may start to pick pockets.

(Dungeons & Dragons)
Rulebook featuring "high magic" options, including a host of new spells.