Advanced Echo item?

We've got Runic Echoes coming up, and Luden's Echo in existence. Why not make a echo item like Kircheis Shard, and call it a category of items? Something like...

Arcane Mirror - 900 gp Build: Amplifying Tome + 465 gp 40 AP Gains charges upon moving or casting. At 100 charges, the next instance of ability damage you deal will expend all charges to deal 30 bonus magic damage to the first enemy hit.

Could maybe even add another echo item eventually, better for single-target damage, like...

Claw of Reverberation Build: Arcane Mirror + Needlessly Large Rod 100 AP Gains charges upon moving or casting. At 100 charges, the next instance of ability damage you deal will expend all charges to deal 100 (+10% AP) bonus magic damage to the first enemy hit, as well as amplifying damage to them by 10% for 3 seconds.

Maybe not though.