I was going to call it a Rainbow Blade (which makes more sense for what the spell does), but I feared people would misread it as more of a political statement than anything else.
So, my idea, is for a spell that grants the caster a minor blade from every school. It could be made a Balance school spell, or a Shadow pip spell. Since Elemental/Spirit blades cost 1 pip for 3 blades, maybe a Palette Blade is 2 pips for 6 blades.
It would give the same percentage of a blade to every school, so a 15% blade for , , , , , , and .
It would be able to be enhanced with a Sharpened blade and be stackable as well. I'd say this is something that should be trainable to all schools, and no earlier than the end of krokotopia (since that's where the Triblades get taught). Perhaps it's something to learn in Celestia since that's where the Astral Spells get taught. Perhaps it's a reward for finishing all the quests in Celestia (that were there at the time Celestia was released), Main and Side quests alike.
Now, the question is, would this be able to be done with the new power flow charts without making things over the top. Is this needed? Naaah, but it would be fun :)