Oh my! - those bicycles are beautiful works of art. You are right, the Art Deco skirt guards are pure poetry. I love the carrier mounted gas tank and the chrome flexipipe on the exhaust. For many years I owned sidecar outfits and I loved piloting them at speed; - my health isn't up to it now and I really do miss them. A little Watsonian copy sidecar could be a good project though, - we shall see.
My Mixte will be more styled after British Utilitarianism than anything too artistic. All that black enamel and 'Rudge Whitworth' transfers/decals will be about sitting up straight and thinking of England rather than giving into hedonistic impulses