Brainstorming Fantasy Trilogy Ideas...

I got this idea from an 'Idea Pool' down at Castles, Quills, and Cameras. Be sure to check it out; it's an amazing blog!

All right, so, let's say that the MacGuffins for my fantasy trilogy are musical instruments. That would be a good idea, since I'd like music to play an integral part in the book.
So, let's say that the three instruments are a drum, not unlike a bodhran; a flute; and a lute.
Each of them could have a magical song you have to play. And each specific song calls up some sort of...thing.
Maybe the drum could call up thunder and lightning storms. And the flute could call up water. The lute could summon the wind, maybe?
If so, the titles of my books could be as follows:

The Songs of Old: Windsong
The Songs of Old: Rainsong
The Songs of Old: Thundersong

That would be nice. Three instruments, three books, three main characters to use them. Ingvar could have the lute, Terran could have the drum, and Keallan could have the flute. Technically, that even fits with their characters! Keallan is related by marriage to the Elves, whom use flutes as a major part of their music. Ingvar has played the lute since he was a young boy in Evenir. And Terran harbors so much pent-up anger and loathing towards Rarrick that he needs to get out; a drum would be perfect for him.

And maybe there could be a fourth, unknown musical instrument, and owned by none other than Lord Rarrick. It could call up something like...rock, or earth, and it could be, like, a Celtic harp. "I summon the Earthsong" or something like that. Or, if I manage to fit a fourth book in (although that's doubtful), the title could be:

The Songs of Old: Earthsong

And Rarrick could have stolen it from the Dwarves. It would fit, y'know. I already planned for each of the MacGuffins to belong to one of the major kingdoms/realms of Elani.
So, for instance, the relations could go something like this:

The Rainsong (flute) belongs to Daerdan, kingdom of the Solas Elves
The Windsong (lute) belongs to Cambria, the Western Realm
The Thundersong (drum) belongs to Evenir, the Eastern Realm
The Earthsong (harp) belongs to Kazad, kingdom of the Dwarves

Hmm. It actually seems more likely for the drum to belong to the Dwarves. So perhaps I should switch instruments so that the Thundersong is actually a harp--no. It only makes sense for it to be a drum, because of thunder and all that. Besides, I kind of like the contradiction of the Dwarves, commonly a gruff, rough, and tough people, playing music on Celtic harps.

And it would be interesting if the musical instruments were created with the intention of teaching peace of mind and serenity in chaos to the user. For instance, whoever is using the instrument might have to play a specific melody, and speak an incantation. Now, obviously, they'll be in the middle of great danger while doing this; it'll take a lot of serenity and courage to be able to do that without messing up.

The incantation for the Rainsong could be something like, I call upon the Rainsong, the one that can give life; the one that can take life. I summon the rain. I summon the seas, the oceans, the rivers. I summon the Rainsong.

And then maybe the instruments don't actually summon storms and wind and all that; maybe they summon animals or humans with magical powers to fight. Or maybe it can just summon the actual storms. Or...

Sheesh. Brainstorming this has gotten me majorly excited. It just might be the motivator I need to finish my trilogy once and for all.