Well, I created Prismatic Missile for anyone who wants to use it, don't have to use this version but its just my take. Material component to help balance it a little in case, as CS suspects, it might be a bit overpowered.
Prismatic Missile
Evocation
Level: Sor/Wiz 9
Components: V, S, M
Casting Time: 1 action
Range: Medium
Targets: Four or more creatures, no two of which can be more than 15 ft. apart
Duration: Instaneous
Saving Throw: Yes (see below)
SR: Yes
Upon casting this spell, you create 1 Prismatic Missile per 4 caster levels (no maximum), which dart out of the caster's extended hand.
Each missile strikes unerringly, even if the target is in melee or has anything less than total cover or concealment. Specific parts of a creature cannot be singled out. Inanimate objects (locks, etc.) cannot be damaged by the spell.
Each missile deals a random amount of damage depending on its color on the chart:
1d8
1-Red Missile-Effect: 20 points of fire damage (Reflex half)
2-Orange Missile-Effect: 40 points of acid damage (Reflex half)
3-Yellow Missile-Effect: 80 points of electricity damage (Reflex half)
4-Green Missile-Effect: Poison (Kills; Fortitude partial, take 20 points of damage instead)
5-Blue Missile-Effect: Turned to stone (Fortitude negates)
6-Indigo Missile-Effect: Insane, as insanity spell (Will negates)
7-Violet-Effect: Sent to another plane (Will negates)
8-Dual colored Missile: roll again twice, ignoring any "8" results.
Material Component: A shard of multi-hued glass worth at least 1000 gold.