Is there a way to do this? Probably, because Wizards, but still

[SangoProduction]

Is there a way to spend more spell slots for a more effective spell, instead of just using a higher level spell slot?

[Kelb_Panthera]

Versatile spellcaster comes to mind. So does Ultimate Magus. Did you have anything more specific in mind?

[Rebel7284]

Versatile Spellcaster can be used to apply metamagic.

Alternatively, circle magic allows you to use someone else's spell slots to make your spells more effective.

Also there are a few spells, such as Assay Spell Resistance and Spell Enchancer that make other spells better in some way.

[SangoProduction]

Does Versatile Spellcaster even work for if you metamagic a spell? Would that allow you to cast a spell that's been metamagiced to one above your max spell level (before VS), or does it just save your high end spell slots?

[WhiteBread]

Well you could use Divine Metamagic for divine spells. You will use Turn/Rebuke Undead attempts instead. There are some ways to make spells divine even if they are arcane like Southern Magician, Geometer PRC and 1 more thing i forgot about.

[Kelb_Panthera]

Does Versatile Spellcaster even work for if you metamagic a spell?

I don't see why not. A spell you know is a spell you know, whether it's being modified or not.


Would that allow you to cast a spell that's been metamagiced to one above your max spell level (before VS), or does it just save your high end spell slots?

Again, I don't see any reason it wouldn't.

[ExLibrisMortis]

Mind Mages can spend spell slots to improve psionic powers, and power points to improve spells, through metapsionics and metamagic respectively.