hmmmm....
...well, I can think of several people who live in Historic Kenwood and are experts on historically correct renovations, and/or are very good contractors. However, I would never post anyone's full name on the internet without permission, as I don't want to violate anyone's privacy. So, instead, let me suggest that you call the city because our city is rich with knowledgeable folks on such matters. I'm not sure what department to suggest, and I don't see ''Neighborhood Design Review'' listed in the city pages of the phone book, but maybe I'm missing it. I think if you ask the city for someone in their neighborhood design review program, it would be a good starting place. You could also come to a neighborhood association meeting and ask around, as our association is also rich with excellent contractors, planners, experts on historic structures and design, etc.
Just curious: Do you know what architectural design style your house is, i.e.: Bungalow, Tudor, American Foursquare, etc.? Because if it is vernacular or minimal traditionalist or something, I could see adding a second story, but if it is a classic bungalow--and this is just my opinion, so take it for what it is worth or chuck it in the trash, either way is cool *lol*--I would hesitate about changing a classic historic structure so massively. But if you go about it with a sensitivity to the historic design, I guess there are ways to do things that are ''historically correct'', if that is even a term. Ask around--there are lots of knowledgeable folks in HK and in the city of St. Pete who can help you.
Good luck!