Err...sorry.  But I *really* want to get this right.  
This is what I gathered from these couple 
days of discussion...

(1) all physical cels started from a douga so at 
one point...they all had a douga.

(2) genga's are rough concept ideas made by 
the Key animators...and *only* those sketches 
are called gengas

(3) layouts are not gengas

(4) sometimes...only the people that worked 
on the anime know which are "merely" rough 
sketchs and which are genga

Questions:

(1) I know that even series that are CG-ed 
have douga's ...but do they have a douga for *
every* frame?  You would think...just the key 
frames or difficult transitions would require 
douga's but a little hand movement or simple 
hair blowing...would be easy to modify using 
the computer...?? anyone know?

(2) Is there basically no way to tell between 
rough sketch and genga?...either than asking 
someone that actually worked on the anime?

(3) I have a complete scene sequence...it 
contains, douga, layout (also has background 
layout)...and it has another set of sketches that 
seem somewhat redundant.  These sketches 
are almost exactly like the douga...what are 
these for?

(4) Does anyone have a website that clearly 
explains everything...?  Sorry if I missed it.  

That's it...^_^