I have to admit that it sounds like fun to me too.
Make them 2 sets of twins, identical twins, but in the wrong pairings - 1 pistol wielding sea dog and one ex gentleman in each pairing. Seperated at birth, so the pistol wielder looks just like the ex gentleman in the other pairing, and vice versa.
Have a pre-game where each group ends up blamed for what the other group does. Hilarity follows...
I think I've been looking at 7th Sea for too long...
The Auld Grump