I would be apt to say brainchilds, since the -children option would seem to focus more on actual 'kids'. I must admit I'm at a loss with this one.
Naturally, I consulted my favourite online dictionary http://dictionary.reference.com/search?q=brainchild, and oddly enough, the plural isn't commented on.
Here's hoping someone can clear it up so we come out of this the wiser!
- For Teachers