Congratulations! I am sure that you have been waiting and planning for a long time to build this home.
Not knowing your preferences or the style of home you would like to build, let me suggest some areas. If you are looking for waterfront, I would suggest the Apollo Beach Area, with the prestigeous private, gated communities of Andalucia and Syphony Isles (only 23 lots available 179K-950K), upper tier homes priced at 4.5M.
Apollo Beach has wonderful canals and direct bay access lots whether you are in the gated communities or not. If you enjoy boating, fishing, golfing or just watching the marine life, this is a great waterfront community. Ruskin, is the neighboring city and you can find some larger parcels of land with bay access and on the Manatee River. The Alafia River is another great choice to build on.
Depending on the size of the home, you may want a mini estate of perhaps 5 acres (gated, private community), then I would recommend Hammock Oaks where the avg. home is around 5,000 sq. ft. heated up to 14,000 sq. ft.
If you wanted an equestrian area, I would recommend Riverview and Plant City.
To be perfectly honest, I don't know where Ft. Lucie is. Would you perhaps mean Port St. Lucie?
If you wanted to share more specific criteria e.g., lot size, preferred ammenities, approx. square ft. of home, waterfront vs rural, gated community vs non deed restricted, style of home, I could narrow down the search in regards to recommending an area and if you prefer, some custom builders who could complete the dream.
I am sorry this information is not complete but I hope that it may help you.