Mark,
What an awful experience. It seems to happen to everyone, - remember the tank in Nature Aquarium World 1 where he comments there are no fish because the PH probe came out the water and the CO2 went flat out? Before you strip it down I suggest you walk away for a day or 4 and take a deep breath. In my experience these situations can always be salvaged easier than you would think in the heat of the momemt. In any case, as discussed - there was a problem with lack of depth, so this is a great opportunity to fiddle with that.
Remember after my blackout when all the crypts had vanished...? I never spent a penny on extra plants after then, they just all grew again. There have been occasions when I've just wanted to cry and give it all up, but sometimes I think it pays to be stubborn and persevere.
Get the CO2 running at a low level, fish out the dead fish, and then take a breather for a couple of days before you decide what to do.
Thoughts are with you mate.
Ray