Interesting theory, about the super champagne. I suppose a genetic glitch could occur on occasion that would cause a super to appear from a normal breeding. (Like hatching a BEL from a lesser to normal pairing). Extremely rare, though.
There seem to be far fewer dominant ball python mutations than there are incomplete dominant ones, and people are extremely quick to label a mutation 'dominant' if they don't see a super form appear in a few breedings.
A morph is only dominant if you can get a super form that looks exactly like the single gene form, but produces 100% morphs when bred to a normal. Otherwise, it hasn't been proven to be dominant. For example, the spider morph--NOT dominant. The absence of any super at all, identical or different, tells us that it's not a dominant mutation. If it were, the super would be identical to a single-gene spider...not missing completely.
So, if no super champagne (that produces all champagnes when bred to a non-champ) has been produced, then it's not proven dominant. It COULD be another co-dom with a lethal super form. Considering how squirrely some champagne combos seem to be, it's not unlikely.