Here's a Marriott in Hollywood FL that might fill the bill for you.

http://www.hollywoodbeachmarriott.com/

My other fav FS Marriott would be Harbor Beach in Ft. Laud ... and if in south beach the Marriott there is small and intimate in an exciting area.

For families ... Marriott BeachPlace Towers in Fort Lauderdale or Marriott Ocean Pointe in Palm Beach Singer Island area.

http://www.marriott-timeshare.com/vacation-resorts.jsp

Brian