I use this:
envoy messenger bag
Built tough for military use, it has pockets everywhere an fits three, two inch jepp binders, license, VFR charts, handheld GPS, torch etc. It also has pen pockets and water bottle pockets which I use to keep clean rags in. Not specifically built for aviators, it definitely suits our trade. Better than any of the "pilot bags" I've seen out there.
Sits nicely between Cessna/piper twin seats, and looks like it will stand the test of time.
It is comfortable to carry across the tarmac and you can hang your headset bag off the side from one of the many loops/straps.
Enjoy.