I think one other Jund poster here used to run Swan Songs on the sideboard. I have never tried but I have mixed feelings. It IS a hard counter vs combo, but it will weaken your manabase and steal too many sideboard slots. Like.. one US and 3 Swan Songs to make it pop up in your hand? 4? That's already 1/3 of your sideboard. I'd say stick to the discard plan!
That was me, and that was some time ago.
It was good, but it is essentially a two card combo (sea is easy to fetch i know). However you dont wonna cascade into SS with BBE and i generally dislike having lands in the board (i didnt have the sea maindeck as that just seemed clunky).
It seems perfect for SnT, but duress+pyroblast and all our mainboard discard is in my opinion better since you get to stay with your jund colors and and dont have to rely on having a fetchland AND SS.