Emulating metamagical feats with spells

[Dakkareth]

Emulate <feat>
Transmutation
Level: Sor/Wiz ???
Components: V, S, F (XP?)
Casting time: 1 action
Range: Personal
Target: Self
Duration: 1 round/4 caster levels
Saving Throw: Will negates (harmless)
Spell Resistance: Yes (harmless)

The next spell cast within the duration of this spell works as if it was prepared with the metamagic feat <feat>, even though it was prepared at its normal level. Thereafter, or if no spell is cast the magic disperses.
In order to cast this spell the caster must have <feat>.

Should this spell be allowed at all?

If yes, at what level should it be for the different metamagic feats?

 

[Byrons_Ghost]

I think it really depends on the feat in question- I assume the different feats will be different spells, yes? If it can emulate any metamagic of the caster's choice, that would be pretty powerful.

Otherwise, I would scale it based on how the feats are scaled in their write-ups. Emulating a silent spell might be a 1st or 2nd level spell, while emulating a twin spell would be four levels higher; eg 5th or 6th level.

One thing to keep in mind is that the effective level raises often keep casters from using the metamagic feats with their more powerful spells. A 7th-level caster can easily get the Widen Spell feat, but since it adds 3 effective levels they can only use it with cantrips or 1st level spells- a widened fireball would be the equivalent of a 6th level spell. Your method would circumvent this- the question becomes whether trading two third level spells for an equivalent sixth level spell is an even tradeoff, or unbalancing.