The only control that seems to be made in the old style used on sailboats is the one below from Seastar. I just browsed their catalog and it is all I could find. I'm not sure of the price but can check tomorrow.You might find an older Morse 2 lever system more to your liking if you don't have a 'kill' cable setup.. but surely there's a fuel cutoff on the engine and all you'd need is a 'manual choke' pull cable kit to rig it up.
Morse used to make a 2 lever system where the levers could be removed and stored off the hub so there was less likelihood of lines getting caught on them.
The other option would be used. There must be some 2 lever controls around in your area. I know there is in Victoria. As far as the cables which are probably original they can be replaced for not very much if necessary. You will likely not need cables as long as the current ones.
As far as I know the throttle, when pulled to the minimum setting, also cut fuel flow to zero for engine stopping. I have basically the same engine as Chris does.