Maico triple would look great with a sidecar-on each side!!
Seriously-Suzuki and Kawasaki had one so just use theirs.
I recall from the Italian sidecar cross GP in '87, Folan had two Husky barrells together-sounded like a banshee or the second coming of Christ! while a Russian team had two Cagivas in together that sounded very sweet but still ran down the pack.