I think as long as you can afford it, that'd be a great idea.

She sounds like a teacher who really cares about the students, and even just the gesture alone would show her the parents notice and appreciate what she does and make her feel good. Maybe include a little note explaining that, too.
I totally feel you on the manic ideas wanting to be
too nice or helpful. :P But this doesn't sound like that, I think it'd be really sweet.