Is there such a thing? Has anyone used it? Does it hold up in Florida HEAT and humidity? Finally, how would I attach fondant decor to it? I have used buttercream before, but I can't take it outside because it melts badly. Everyone loves my fondant covered cakes, everyone but my husband. I'm tired of having him complain. Thanks in advance for your help.

Your buttercream melts because you are using real butter. Use a crisco (shortening or hi-ratio shortening) instead of butter recipe. Here's a link to a very popular recipe that holds up very well in humidity:
http://cakecentral.com/recipes/6992/indydebis-crisco-based-buttercream-icing

Here's another thread I brought up (haven't read it, but there are a LOT of entries) using search terms "crusting buttercream high humidity)

http://cakecentral.com/cake-decorating-ftopict-288073-crusting.html+buttercream+high+humidity