I have a mud oven built from the book "build your own earth oven" by kiko denzer. It's technically cobb, which is not quite adobe (different mix of materials). I can fit about 6 loaves at a time, but it stays hot long enough for multiple batches.
If I were doing this on a regular/commercial basis, I'd probably go more along the lines of a masonry oven (see the Alan Scott book "the bread builders", which has plans for a small brick oven -- but a lot larger than mine).
Baking for folks other than yourself includes a lot more than the oven, so you might want to look into your local rules and regulations for baking out of your home. That might help you narrow down your choices.
Good luck! I am having fun with mine, it's a good way to get started with a small investment of space and materials. I
Here's a link to the thread when I first built it last year:
earth oven link
Oh and the book "Artisan Breads across America" by maggie glezer has some examples of backyard bakers who became commercial bakers. It's a good book to get from the library