I've intended to get a BWY quick disconnect for quite some time, but I like to do big orders with a lot of stuff with them because they're a bit folksy about getting around to it, being a somewhat part-time business as they are, and that's just enough disincentive for me to never get around to it in time to go sailing.
In the meantime, I'm doing this, and it works well:

It's a push-button quickpin (the smallest at West Marine, and a 10-24 knob from True Value. Total cost is something like $20, but I'm not quite sure because I had both parts laying around.
Also you can see visible in the photo the ballast-gate led-aft mod I've done. Setting the the valve in that position while you're filling the tank causes it to whistle loudly enough to hear all over the cockpit so you can tell when the tank is done filling (if the motor's off).
