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)

Hi Jim, I started a new post about this very subject. Sounds like you know something about this. I too retired and need something to keep busy with. With Pa.'s cold winters (zone 6) I would like to keep with hards types with the beauty of the tropicals. It is dreams that start the discovery process. And most of all luck. At some point these two Hibiscus must have had a connection? If so it should be possible to cross-breed them.
Stush