And granted, I've only ever collected Rayearth 
cels, so Dragonball is outside my genre... but
if I saw the cel and douga being sold separately
by the same seller, I wouldn't buy either -
or ANYTHING from that seller for that matter.
It's just a matter of keeping a set together,
I guess... animation isn't only cels.  There are
so many steps involved, it's important to a 
collector to truly understand and appreciate
all of the pieces that make up a chunk of
animation.  The cel is pretty... add the 
(matching)
background and it's prettier... add the douga and
you get a feel for the animation process...
and if you get the genga, then heck, you have it
all, yes?

To slice up the set / matching pair to make some
more money off of collectors just leaves a 
bad taste in my mouth.  Marc can do whatever
he wants with his cels, they're HIS cels...
but if he was selling cels from the show I like,
then I'd go elsewhere.

Especially for shows where there are an insane
number of episodes (DB, SM, etc): why buy one
piece and miss the other MATCHING part of the
set if you may feel cheated about it later?
There are so many other cels... but everyone is
entitled to buy whatever he/she wants.

Personally, I equate splitting dougas & cels
(if done so intentionally just to make some more
money ... it IS kind of neat to see douga show
up a long time later from different sources,
esp. when it matches a cel you have!!  I know
this discussion occured about Taro's douga a
while back) to splitting up layers of a cel...
should I sell Hikaru's mouth separately in order
to make an extra $5?  After all, it IS another
piece of the animation sequence...

Just my chatter from the void.

Hikaru