Padron admitted in an article (don't have the link) the the 80th (and some others in the line) is "treated," (i.e. dyed).
According to several articles I've read and interviews I've watched lately, most maduros in the cigar industry today are "treated" for color in some way. The process varries, and uses various parts of the tobacco plant pulped-down into dye. (Some companies will use coffee or other products for dye as well).
The degree to which they need to treat the maddies varies, as does the quality (I agree that the RP Fusion MM (i.e. "Double Maduro") looks way too black to be "real"). Another example--the 1st-gen boxed RP OWR maduros don't look nearly as dyed, and are actually fairly spotty looking. The newer bundled versions are VERY black, and I'd not be suprised if the color came off if it got wet.
The fact is that well-fermented leaves get darker and darker, and people know that. Therefore, manufacturers stared "treating" their maddies, which forced even the high-end manufacturers to "treat" just to keep up appearances.
The interviews I watched said that "treating" does not affect flavor, smoke, or anything else about the cigar at all--and that proper "treatment" will not turn the cigar into a magic marker.
I'd personally be interested to know if the wrappers used for sticks like La Riqueza and El Triunfador are "treated" at all. They wrappers look amazing, but they are not as dark as others I've seen (like the Padron 80th) so I'd think maybe not. Though it would not lessen my enjoyment if I found out that they were.