I use the largest Lowepro Nova, but when fully loaded, (but with only one body - two wont fit - nor the DA* 300 as it's too big), it's too heavy to carry far, so I tend now to use it to transport my kit in my car, then break it down into another bag for use on the day/shoot if I'm out walking in the countryside, OR, I secure the Nova to a fishing tackle trolley ( which also carry's a tripod) and just pull it behind me if visiting gardens, etc, with hard paths.
My DA*300 always travels in a separate top-loading ThinkTank Digital Holster bag (with or without a body attached) which I can throw over my shoulder or hang from my belt.
My Limiteds all now live in an OpTech Accessory Pack, which, combined with a K-S1 body in a Kata Grip-10DL bag on my belt, makes for a great light-weight kit around town.
Bottom line? There's no one solution.