Here is a wide selection of outdoor firepits, and a majority of them have the capability of being gas powered.

https://www.houzz.com/products/fire-pits-prbr0-br~t_646

There are a couple of ways you can find your local fireplace nerds (gas firepits like above a not generally D-I-Y projects, especially if you're working with propane)

Try the Hearth, Patio & BBQ Association's website and do a dealer search: http://www.hpba.org/retailer-locator

Or you can go to the National Fireplace Institute website and find a certified gas specialist: http://www.nficertified.org/pages_consumers/consumers-1.html