I think just about your only bet is a cab/shuttle service. I think there may be a lower cost shuttle that runs from FLL to MIA airports, and then you could catch something from the MIA airport to the cruise.. hmm.. yeah, ok, sounds like a cab from FLL airport to the cruise in miami may be easiest.
If there are ~4 of you, split the cost and it should come out fairly "reasonable"... you ought to call the cruise company and ask them, I'm sure they deal with that a lot.
Edit: I'll be happy to drive you if you can drop off a cute girl as a security deposit for the duration of your cruise. 🙂
Edit2: Carbo are you insane? That would be a ~30 mile walk?!?