If the question of whether or not you can do brush embroidery work on Italian Meringue Buttercream has been keeping you up at night, I'm here to tell you its possible (names have been smudged to protect the innocent):
Well, my recipe is really a combination of IMBC with "regular" buttercream to make it a little easier to work with, but still. Its not as clean looking as it probably is on crusting buttercream but its pretty and a bit out of the ordinary, so I'm glad I tried it.
It was somewhat time consuming and I don't recommend that you drink a lot of caffeine beforehand as it does require a steady hand with the brush.
I was aiming for clusters of hydrangeas, but I think I missed the mark.