Kevin,
it does seem that most of the good dark purples have more pointed leaves, even in my 'silverine' bee seed patch I've found that to be the case despite a number of wide leaved plants occurring in other colors. Can't pass up the striped ones though! I have two and a half (only the tips) from 'Silverine' that have developed stripes, but I've only noticed them recently which makes me think they might just show the pattern seasonally. One of these I can verify from photos to be a solid dark plant in spring which stripes as it fades. What an interesting effect! I am also very amused by some of my 'Silverine' pinks, I intend to keep a pastel and a more vibrant pink out of that group.
I'd bet those 'Silver Song' x 'Blue Whale's are really spectacular! 'Silver Song' is definitely cold hued, I imagine it would pair well with a blue.
So interestingly enough both of those renowned artists were not only Italian but also contemporaries, Michelangelo came only 23 years after da Vinci.
Cheers,
-Sol