I don't think it's any edition released by Toei.  
I've seen those throughout the 4 years I've been 
collecting, and -every- one of them had some line 
fading of some sort.

I -think- I've seen that image on a cel card 
before, but I can't remember if that particular 
image of Usagi and Luna was on there or not.  
Regardless, the seller said the size is 9x12, 
so...

I really don't think it's anything released by 
Toei, due to the line fading issue, and the fact 
it's not stamped or anything.  My guess it's a 
fan cel/doujin cel...

Hope this helps,
Kristina