OK so I think this sounds highly unlikely (which is why I put it in chat and not news) but according to my friend, who knows the guy in charge of a convention that will start this year, Ayu might be one of the guests/stars.
I told him that I doubt she will go because she's super busy and I don't think she's ever done a convention, but he said it is 'pencilled in'. Not 100% confirmed. He's negotiating with Avex.
Here is the convention's website:
http://amccuk.yolasite.com
Confirmed people are the cast of the death note films, the cast of card captor sakura, DBSK and the Japanese cast of Lucky star.
Just thought I'd share this with you guys and will update you when I get more info =)