I built a mud oven from kiko denzer's book ("build your own earth oven"). This style is based on the canadian ovens (as opposed to the southwestern adobe types) so it should be pretty good at withstanding extreme weather--though most of them do have roofs built overtop.
Pics at:
http://www.flickr.com/photos/breadni...7602168287743/
If you really want to *legally* sell bread out of your back yard, there can be lots of rules based on your local health code, so this might not be the best option. But, to get an idea of the process of baking with this type of oven, without the expense and permanency of a masonry brick oven, they're great.
Here's a few thoughts based on this thread:
The mud walls are solid, like cement, so it doesn't really get dirt on your food. Getting the floor super clean after shoveling the fire out and sweeping can be tricky--I sometimes can have a little ash on the bottoms of the first few loaves baked directly on the hearth. Nothing I mind, but you could bake on parchment paper or in pans to avoid it.
It's kind of a lot of work to use it--an all day thing. For ours it usually takes about 4 or 5 hours of burning to get it up to bread temperatures (600 to start). I mean, you can do other things while it's heating up, but it takes some tending. Say you start the fire at 8 am, you can probably bake by around 2 and it will stay hot for hours. If you get a later start you will be pulling things out of the oven long after dark with a flashlight
So if you are organized (and have some stamina) you can bake and cook a LOT of food. You get it really hot and the heat dissipates slowly, so you kind of arrange your schedule based on that--pizzas/breads first (500-600), then roasting (400+ degrees), then you can do other baking when it gets to 350 or so. For example, in one firing we have baked several batches of bread, then roasted a couple of chickens and some veggies, then baked a pie, and finished up with a batch of granola.
