Are you talking about REPLACING your hot water system with solar or CONVERTING your electric hot water tank?
Electric HW heaters are far less than ideal for installing bigger systems on- they're just not set up right from a heat-exchanger, stratification & higher-temp point of view. But there's at least one simplified system out there designed as a conversion kit:
http://www.butlersunsolutions.com/I've never used it, but it appears to be fairly well evolved, and SRCC rated, etc.
Heat dumping isn't rocket science, and dead-easy to do with flat panels (run the circulation pump at night to bring the temp down by radiating the heat out to the sky with the panel.) This approach can't work with evacuated tubes though.
Batch heaters in series with the standard HW heating systems work well in places with low freezing risk like FL (hard to tell how low that risk is this week, eh? ;-) ). The better versions have internal heat exchangers that carry the potable water, and the thermal storage is basically "dead" water that remains. (eg:
http://www.harpiris.com/home.html ) With that approach you limit the risk of legionella from stagnation at tepid temps, because with less than a gallon of potable water in the heat exchanger it's fully purged at nearly every hot water draw. With potable bulk at tepid temps it's a prescription for getting the biology going down a dangerous path. (Bulk potable water needs to be stored at temps under 80F or over 120F to limit the risk.)
Flat panel batch heaters with internal storage essentially self heat-dump. When storage temps are over 150F they radiate quite well, but at 100F, not so much. If the batch heater is delivering 110-130F water into the electric tank it's duty cycle is near-zero. If your batch heater volume is 75% of your daily use it'll be delivering nearly 100% during the summer months (due to higher temps than your electric tank setpoint. The hot water volume needed to mix to 110F for the bath is less with 140-150F water than with 125F water.)
Price/performance wise batch heaters rule, since they're simplicity itself- no pumps no loop plumbing, no glycol, very simple plumbing & very low maintenance. I wouldn't bother with freeze-resistant evacuated tube versions in Tampa- flat panel batch heaters are cheaper per delivered BTU, and have less (or no) need for heat dumping provisions should you decide to go on vacation for a couple of weeks in the summer (the Suncache warranty is good for up to 90 consecutive days of stagnation!)
I neither sell nor install these systems, but the flat-panel batch heaters with internal heat exchangers is the way I'd go if I lived in Tampa. A single 50 gallon version like the Harparis SunCache is likely sufficient for your situation, unless you're planning on filling large soaking tubs or spas on a regular basis (in which case 2 would probably do.) If Harparis doesn't have competition, I'd be surprised, but I'm not up on the latest-greatest batch heaters, since most are inappropriate for my climate.