I will respond with photos and more information later on.
In my opinion, a BCI male or female would be a much better handling and display option. You can certainly grow a large male or female but age is the key to ultimate end size of a healthy BC. Note HEALTHY here.
A Dumeril boa displays much of the same behavior that the royals you already own do. "Dumeril Ground Boa". You will get a semi arboreal experience with a properly set up BCI. At least some of the time. As far as beauty, I will post photos of a 6 foot male locality Colombian BCI from Barranquilla that will rival the beauty of many BCC boas.
Nothing against Dumeril boas, but they are not a big change from what you have with royals and don't display as well as BCI/BCC.
What is it your it your girl does not like about boa constrictors?
You can get some stunning BCI and BCC specimens for $300 and under.