mercurio,
Here's an alternative to your Ceremonial Spell feat.
Dave
OVERCHARGED SPELL [METAMAGIC]
Prerequisites: Knowledge (arcana) 6 ranks, Spellcraft 6 ranks, any one other metamagic feat
Benefit: When you cast a spell, you can increase the casting time to increase the effect. For each round spent overcharging a spell, its duration, range or area of effect is increased as though the caster were one level higher; he can only choose one of these three facets to increase (he cannot overcharge the range and duration of the same spell on the same casting). A spellcaster cannot overcharge a spell for more rounds than he has spellcasting levels (i.e. a 7th level wizard can spend up to 7 rounds overcharging a spell).
Overcharging is taxing on the caster--for each round spent overcharging, the caster must succeed on a progressively difficult Concentration check (DC 10 + spell's original level + twice the current round of overcharging). Failing this check causes the spell to fail. A spell cannot be made more powerful than the maximum allowed for a spell of that level (i.e. a spellcaster cannot create a 12d6 lightning bolt). The caster cannot Take 10 on this check. The Combat Casting feat does not modify this use of the Concentration check.
The caster must declare, at the beginning of his turn each round, whether he intends to release the overcharged spell or continue overcharging it. If he releases it, he can still take a move action after he releases the spell. If he wishes to overcharge it, then if he succeeds on his Concentration check, he can only take a 5-foot step that round (holding an overcharged a spell requires a full round). If he tries to overcharge a spell but fails his Concentration check on any given round, then he can take a move action after he misses his check.
When the caster is overcharging a spell, he can be disrupted on any round that he's making his Concentration checks. If someone else distracts him (see PHB entry on Concentration skill) then the caster may have to make additional Concentration checks to continue overcharging. Another spellcaster cannot counter-spell a spell that's being held in this way, but the spell can be counter-spelled when the spell is released.
For example, a 5th level wizard wants to cast a fireball as a 10d6 fireball; this will require 5 rounds of overcharging. On the first round, he casts fireball; if he succeeds on a Concentration check (DC 15), the spell is not discharged (and if he fails, it's wasted). On the second round, he can choose to release the fireball (it's now a 6d6 fireball); otherwise he can continue overcharging if he makes another Concentration check (DC 17). On the third round he can release the 7d6 fireball or make another Concentration check (DC 19); on the fourth round he can release the 8d6 fireball or make another Concentration check (DC 21); on the fifth round he can release the 9d6 fireball or make another Concentration check (DC 23). Finally, after five full rounds, the caster's sixth round comes up, he must now release the fireball, and it's a 10d6 fireball.
NOTES
You might argue that a 5th level caster shouldn't be able to cast a 10d6 fireball. Okay, point taken--maybe I need to modify down the total power of the feat. But, let's look at a 5th level caster with a +9 Concentration check. Since he can't Take 10, there's a 1-in-4 chance that he blows the whole thing on the first round. On the second round, he has a 35% chance to blow it. On the third round, there's a 45% chance to ruin the spell. On the fourth, there's a 55% chance, and on the fifth there's almost a 2-in-3 chance that he'll fail. So, overcharging for the maximum effect isn't likely to work at lower levels, but it gives the player the option of risking total failure against a more powerful result.
