Lowepro Flipside 400AW should fit your gear I'd have thought. It would definitely fit the gripped 7d with 70-200mm f2.8, and should fit a gripped 550d with 24-70mm f4 and other smaller lenses, but it's just whether it would fit the 550d with 24-70mm attached or whether they'd have to be separated off. The Flipside 500AW should fit it with ease but may end up being too big?