Best to have cel/douga for Yuu Watase to sign.

She only did a few sketches.  Majority were
done for AZ con staffers.  Then that really
nice colored one of Ceres that they auctioned
off.  

Only one she did free for a fan that I know of 
was a little Nuriko drawing for the woman who 
hosted the Nuriko birthday party last year during 
AZ. Can see the little sketch at 
http://www.nuriko.net/WataseNuri2.jpg