Packrraat, If you are planning to leave carpet in the rest of the room, no reason to pay a professional to take it out from under where the hearth will be. Just plunk the hearth on top of it. I was just saying that I would lose the carpet in that room, or at least the parts of it near the stove. If at some later date you decide to take out the carpet in the rest of the room, you won't probably want/be able to do anything to the floor beneath the hearth and extremely heavy stove, so that won't matter much, just make the transition area a little trickier.
I am admittedly anti-carpet, hubby has lots of allergies and carpet is not a friend to allergies. We have lots of parties, too, and that tends to lead to spilled drinks, which also make carpet suffer, as well as all the wood traffic. We have a raised up hearth, and we store about 3 days of wood underneath in the slots between the support legs, so the Rubbermaid idea wouldn't work for us. You can see what we did with our hearth and Phoenix stove in the Perfect Picture forum. We had wall to wall carpet, rolled it all up and gave it away on freecycle (several people wanted it!) and put down vinyl tile flooring. That was 1/2 to 1/3 the price of actual wood, and very easy to clean, and if we ever burn a square, we just plunk another one down. Ceramic tiles are actually pretty cheap on sale, too. Just a thought.