The Signature Tower in Nashville will soar to just 50 floors instead of the 70 floors originally planned. The economic downturn prompted developer Tony Giarratana to revise plans for the mixed-use tower. The plans now call for replacing hundreds of small condos with a few luxury condos. Giarratana said it isn't clear how the changes will affect the cost of the building, which was originally estimated at $250 million. He noted that the cost of materials and labor have declined recently.