You can always draw a picture of what you want and like KTsnake said, take it in to a jeweler. The jeweler will then have to make a mold out of wax and then get your go-ahead. After than he or she can do the gold work and any antiquing and set stones. However I'm letting you know (cuz I work in the business) that it can get very expensive. Usually it costs $600 for the mold and wax...and gold prices are thru the roof ($420/oz.). So if you can find one you simply like better than others, I'd almost recommend ordering a pre-made one
Good Luck!