RockChick is right, and I've been told that the following hotels also offer what you're looking for. Holiday Inn Express - Rocky Point, Hampton Inn Tampa/ Ybor City, or perhaps LaQuinta Inn on West Spruce Street, Tampa. I've personally never checked any of these to see exactly what they offer. The Ybor City area is VERY close to the port, and the Rocky Point area is water front, on old Tampa Bay. LaQuinta Inn on W. Spruce St. is a very good central area, with lots of shopping, and good restaurants, so any of them should be O.K. Like RockChick says, cab fare to the port from any of these should be very reasonable. I don't know much about the rental car agencies but I'd certainly ask them. If you have to park at the port, it'll be $12 a day, or perhaps by then more. Parking is in a secured indoor garage, which they lock up when the ship sails.
Have a GREAT cruise.