The squash apple bake turned out decent, but did't quite satisfy whatever it was I thought I was trying to create. It was not bad though, and I think sweet potatoes or yams might even be better. I'm still looking for the ultimate squash recipe for pumpkin style squash.
I suppose a bigger oven means more rocks, clay, sand, straw and labor. I'd want it to also be an aesthetic fire-place for entertaining without baking and serve as part of a larger outdoor kitchen complete with direct access to the garden. It would also be totally possible to roof the oven with slate and/or lime plaster if you didn't want it under a larger structure. It could also be made so that cooking with pots and pans with the same fire would be fairly painless. You got me thinking. I've seen something like this somewhere.