Case for G6+14-140?
Nice choice with the G6! I was in the same situation you were with, lacking a bag, so I registered just to see if I can save you the trouble I had Specially after I failed buying a USAgear neoprene sleeve which was supposedly compatible but ended up being way too big for our camera.
I stumbled across a 'Hama Syscase Colt' at a local store and it fits perfectly. Regarding width it is just fine, regarding length I can just tell you that, with the kit 14-42 on there is still enough space on top so the 14-140 should be fine.
Just for you to have an idea, I fit in my Olympus 45mm (with its own neoprene sleeve) on top of the camera and still can close the zip without too much effort. It bulges a little bit at the top when I do that, but that means G6+ 14-140 should be perfectly fine.