Some people claim success by...

cutting their tropical hibiscus back to about 6-8" tall and storing them in the garage, basement or a room in the house that they keep closed and used for storage -- little or no light.  The temperature stays somewhere around 40° to 50° F -- never freezing. These are left alone -- no watering. In the spring, they are put outside, watered and fertilized, and they bloom months later. Try this at your own risk. When some long-time tropical hibiscus growers were told about this technique, they thought it meant certain death for the plants. However, there have been a number of reports of success. It probably works best with the common, older varieties like Brilliant, President, Painted Lady, etc. because they are known for their sturdiness. Whether it works for the fancier, exotic hybrids that are often grafted, we don't know.