I've seen cels of Operative A pop up every once in 
a while, usually on eBay.  I can't recall off hand any 
dealers that have had cels of A currently, or even 
recently.  They don't seem to pop up too 
frequently, but they do come around..  
Patience is a virtue, and one which I know I do not 
have myself, but unfortunately it seems to be 
necessary when collecting cels of characters with 
lesser screen time. =/  I'm sorry it's not exactly a 
load of help, but the best I can say is to keep 
waiting, and keep your eyes out..  They come 
around every so often, one just has to wait.
Hope you find a good one, eventually. ^_^

~Mala