Hmm, that might be on the sweeter side, but I think as a separate drink it could work. Or maybe half bonal/half dry vermouth? Bianco is great for a handful of drinks (especially Eyeore's Requiem) but not as versatile as regular sweet/dry vermouths.
They have JM Blanc at liquor world in Porter. It's the best white rhum agricole for cocktails, I think, as it's assertive but not INSANE like some of the others I've had, like the Duquesne bottle I have that is awesome but completely overpowers any other ingredients.
This is one of the few drinks I've made up that I go back to on a regular basis - basically whenever I have a bottle of bianco open. I'll have to try it with dry vermouth - actually, dry vermouth and rhum agricole makes a lot of sense to me, although that's a dry starting point for any cocktail.