Cels Forum

Instead of Chinatown, I'd go over to Post street in Japantown.
The kinokuniya bookstore in the upper level of the kinokuniya building 
has cels for sale as well as art books and more manga than you 
can shake a stick at.. :P

They don't have a lot of cels and you have to ask to see them 
at the counter. 

And if your inclined to, head over the bridge and visit Mikado.
They have some R2 dvd for sale as well as LD and CD's.