Yes, oliver - I do have some sketches that are 
colored on the opposite side from the drawing. I 
also have (or have had) a couple sketches that 
had things like mouths drawn in reverse on the 
opposite side. (So that when you hold it up to 
the light, you can see the mouth in place.)

But anyhow, people don't seem to show the 
sketches when they're selling a cel, but for this 
cel, it was the seller's scan of the sketch that 
sold me on the whole cel. ^_^

Oversized, from Cutey Honey OVA. ^_^

Many Sharp Smiles,
--Drac