COASTROAD Hearth & Patio The short answer is: There are a lot of ways and YES.

Pizza ovens are more complicated than open fireplaces, but depending on how serious you are about having a real, workable oven outside or if this is more for aesthetics, you have some options.

Woodstone is company with a tried-and-true track record in the restaurant industry. They now offer ovens for residential use: http://woodstonehome.com/

There are companies that make prefab ovens that are complete, like these Mario Batali Signature ovens: http://www.batalibrickoven.com/about-ovens.html

And there are real masonry oven domes that can be made into ovens, like these: http://www.wildwoodovens.com/ovens/milano.toscano.php (not too pretty to look at, but a good basis for a functional oven)

The biggest visual differences between what you might consider a fireplace and an oven are:
1. the opening size - an oven shouldn't have an opening much larger than the size of a pizza peel to keep the heat inside; a fireplace should have a large opening to reflect the radiant heat outward toward the front.
2. the height - an oven should be a convenient working height, from 36" to 48" off of the floor; a fireplace should typically be anywhere from flush with the floor to no more than about 20" off of the floor.

Beyond that, the science and technology that goes into an oven design is much more sophisticated than a typical fireplace. Not necessarily a D-I-Y project, unless you purchase engineered components.