The short answer is "No". That said, the Fleming Brothers have developed at least three cultivars that they have patented, or are patenting, that they assert to be hybrids of hardy hibiscus and exotic tropical hibiscus, of the rosa-sinensis complex. However, I have a "backyard hybridizer" friend who seriously questions their claims. That said, I DO have one of these plants, Pink Comet which at least hints at having rosa-sinensis genetic material in its heritage. I have also read that hybrids of rosa-sinensis, and Hibiscus syriacus( The Rose of Sharon)have been created. I have not found them on the market yet, however. DO give it a try! You just MIGHT get fortunate! Subtropical hibiscus, such as Hibiscus grandiflorus of Florida, will cross with certain hardy hibiscus, such as Hibiscus moscheutos. These can be truly spectacular. One such hybrid is Hibiscus 'Moy Grande'. This was developed by a Dr. Moy, of San Antonio if memory serves me right. It is worth obtaining. I can send you seed, if you tell me your name and address. You can contact me at :jrandjimr@comcast.net Sincerely, "Palmfan" (Jim Reilly)

Ed, its too late in your zone to plant it now and absolutely know it will make it thru the winter. Unless you really mulch it well. Your hardy hibiscus will easily make it through the winter next year. Just keep it in your sun room or porch til the spring and then plant it outside. It might bloom, but probably not. The rose of sharon also, very hardy, You can plant that out next spring too if you want. Almost all hardy hibiscus will live in the ground down to zone 4 with mulch.

On my daily walk today this tiny flower caught my attention...A search of my weed ID books led me to believe it could be an hibiscus trionum. But the centre of the flower does not seem to be identical to the photos presented... Image link:

You say you have Mediterranean type weather, so I have to assume you are at least zone 8 like me. I had one, plant it in the ground with plenty of composted cow manure, and mulch well. At least 2 inches. Water it every day for the first week, then taper it off to every 3 days or so. They are hardy plants in the right zone. When you see it needs water, water it. It will come back next year, but get it established now, so it has a great root system already established for the winter. Add additional mulch for the winter too.