I've got a pile of settei sheets (for a cel-
animated show) which are photocopies. I think it 
would be difficult to find the "original" hand-
drawn settei from which all the others were 
copied for the animation team, so having a 
photocopied settei set is more acceptable, say, 
than having a photocopy of someone's personal 
genga or douga or something. Likewise, I know 
that my photocopies were studio photocopies, as 
they've been marked on by the animation staff. 
And in some cases, where I have duplicates of the 
same image, one copy may be of a later generation 
than another copy. It's kind of interesting. ^_^

However, I think that it would be a different 
situation if, say, I decided to take my settei 
photocopies to Kinko's and run fifty copies of my 
sketches, and sell them because I don't want to 
give up my copy. That's just kind of cheesy. :o)

I'd say if you could ever find an original hand-
drawn settei, from which all the other settei 
were copied, it would be valuable, if only 
because it was probably drawn by the art director 
or someone like that... A hand-drawn layout 
sketch is probably less valuable, since those 
seem to be more common, and aren't necessarily 
traceable to any one person.

But in the end, an object's value depends on the 
market, like everything else. :o)