There is mast-up storage on Anna Maria Island (a bit north of Sarasota) on the beach two blocks north of the Sandbar Restaurant. Just pull your boat up to the sand-dune, dig a hole and sink a cinder-block with a big nylon rope attached for a tie-down, and you're all set. There is about 150' of beach between the dune and the Gulf of Mexico. Currently 4-5 catamarans are stored there. You have to sail your boat to and from there though, as there is no trailer access.