I also have a Gibson RD. For several years, I have been thinking about how to combine the two body shapes. Below is my first attempt. The body was made from hard maple. The pickups are made by Carvin.
The guitar was painfully bright and too heavy. Recently, I decided to modify the body. I routed a cavity between the pickups and also increased the size of the electronics cavity. I changed the neck pickup to a C22 model. The guitar is now much lighter and the sound has mellowed. I also removed the old finish from the neck and refinished it.
Here are some photos. I realize the pickguard is unusual and may not be "appreciated" by most. It kind of grows on you. I have since replaced the chrome knob with a black one.
Let me know what you think.
This is the first attempt. Basic in the extreme.

Here are photos of the rebuild.


Here's a photo of the headstock. I added a headstock cap of cocobolo during the first attempt to build the body and kept the original truss rod cover.

Thanks for looking.