I installed a iron gate a month back. It’s simpler than your design, larger in size 12 ft wide by 5 ft tall. Total cost including installation was $1200- in Cash. I got it done by a guy from a company called SD Iron Works. You can call him @ 619 850 4955 and ask him to do the job directly without going through the company. If you show him the design he should be able to make it. He also has an album with number of gate photos- if you want to choose from. You should negotitate the price with him and offer him to pay cash for better discount.

I was getting $3200 price from other places I checked which clearly is a rip-off.