When I went to Mexico City, I fit a pair of hiking boots, a pair of fairly packable sneakers, 8 days of clothes, a laptop, my stupidly large dopp kit, and raingear in a B&R baseline international roller and the baseline expandable cabin bag (fully compressed). (I was wearing an additional pair of dress boots, I'm not reasonable.)
I regularly carry a pair of 11in allen edmonds, with shoe trees plus 2 days worth of suit (1x jacket 2x pants 2x shirts) plus 3 days of casual in my B&R international. With the cabin bag, I get a laptop and a second pair of shoes with lots of room to spare.
I'm also really fat, so if your thinner you can carry more.
Other option, if you don't need a suit is the Tom Bihn Aeronaut 30. It will easily fit dress shoes and 5 days of causal clothes.