i dont really have a solution, and i dont know if this is helpful at all but heres a suggestion.
actually i havent worn anything empire-waisted in a while, but i'm in love with all those peplum-shaped tops and dresses atm
and its probably not difficult to adjust an empire waisted top towards a peplum shape.
as you suggested try adding princess seams down to the waist line, so everything is tighter and more tailored and thus less likely to ride up? you might have to make a cut at the waist and then just add ruffle
i never tried it though and dont know how complicated it is, but as youre reducing the fabric, it should be possible
have a look at this outfit:http://garnerstyle.blogspot.de/2013/12/ethnic-chic.html
(im more of an apple-shape meets reversed triangle, so i would go easy on the ruffles for myself, but it really depends
also it looks like her peplum waist isnt actually that much lower than and empire-waist... yay)