I used to have a fountain pen. There is something special about having to load a fountain pen with ink and hand-write notes, especially in this day and age, when people type everything (emails, forum posts, etc.) and if they MUST hand-write something they use a ball-point pen.
That said, unfortunately, I can't point you to a store or website where you could buy a fountain pen and ink these days.
If you do find one, she'd damn well better write you a thank-you note using the pen!