I too use a wardrobe suitcase (suitbag, on wheels). I use the dry-cleaning bags to great effect, usually putting one outfit in a bag, but sometimes putting three or four men's shirts inside one (have to limit the number of hangers.

I love that bag, but it necessitates carrying another regular suitcase--not much room in this one for other kinds of clothes. It's heavy, but it wheels very nicely, and my matching carryon attaches to the top. The regular suitcase will contain the casual wear. And this way we accomplish the "mix and match"--if one suitcase gets lost, we will both have clothes, albeit all dressy or all casual! I only use a spacebag for undies. Comes in handy for dirt stuff coming back as well.

My carryon will contain cosmetics, camera, jewellery, airplane reading material, a change of clothes, my bathing suit, and a pareo!