I have a Lowepro Whistler BP 450 AW, but it by itself weighs 3.31kg. It will fit overhead on the Q400 planes, but by the time I add everything it must be up to 14kgs at least, I also downsized my laptop to help reduce weight.
Whistler BP 450 AW
Worst I've had is 17 kg on a VA trip in a Lowepro Pro Runner 450 (also use a Tactic 450 which doesn't quite fit as much).
Recent trip to Africa saw me pooping bricks when SQ wanted to weigh the carry on at Check In. Fortunately I'd spread some of it across checked luggage (chargers etc).