Joyka, have you already tried offering this 
person a really large sum of money for the cel 
you want?  I think most of us would be willing to 
give up one cel for a very very large amount- 
maybe I just grew up too thrify, but if someone 
offered $1000 for one of my cels I'm pretty sure 
I'd sell it... I don't know how much you have but 
x cels usually are a couple hundred, if you have 
that much to blow on an off chance I would be 
suprised if the other person also has so much 
money that he wouldn't consider an offer for 2-3 
times what the cel you want is worth.