This actually concerns me, as I was thinking of 
selling my artwork on ebay sometime...I don't 
even think it's wanting a cel so much as 
recognizing someone's artistic talent.  That's 
why I would sell my stuff.  Someone out there 
might absolutely love it, and then it becomes 
just as valuable as any original cel to that 
person.  There's usually not a lot of money in 
fanart unless it's hentai and features someone 
from Tenchi ^_^
I mean, sure there are some companies somewhere 
that own the rights to the shows.  However, I 
think a lot of the fanart's better than the 
commercial stuff (seen the 2001 Weiss calendar, 
anyone?  The last picture of Farfie and 
Schuldig's really ugly).  As long as it's an 
original drawing/cel and, as previously 
mentioned, the person tells everyone it's fan 
made, there shouldn't be a problem.  Company 
ownership shouldn't be able to inhibit the 
creation and distribution of art no da.

Oh, and an update, for anyone who still 
remembers.  I couldn't get the cel of Houki.  My 
dad's making me save up for this trip I'm taking 
to Japan instead.  He just doesn't understand, or 
maybe I don't.  One of us is wrong, at any rate...