Here is a sketch for the album art - tried to capture a few of the elements that really make the nouveau style. The color pallete would use lots of warm earthtones similar to Mucha's work but with a few brighter accents mixed in. I am hesitant to try to make it too much of a direct reproduction of his style, mainly because I'm not sure I could pull it off convincingly enough to not just look like a bad copy. I think maybe something with a bolder line and more solid blocks of color could be really cool though - sort of an updated and modern take on the style. 

The rest of the digipak would carry out the same motif, probably incorporate the floral elements from the cover throughout the rest of the package.