RBDOOM-3-BFG has been one of the more active open-source projects built around the Doom 3 code-base. The main developer behind the project, Robert Beckebans, has been adding new features albeit not too much to report on lately.
However, today he commented on this RBDOOM-3-BFG bug report from back in 2014 that I originally created about the broken benchmark functionality in the code. He wrote today, "I will try to fix this [benchmark functionality] next month. I want this feature in the next stable release and then it is very likely that I will start porting the renderer to Vulkan. I'm very interested in RBDOOM-3-BFG benchmarks between OpenGL and Vulkan."
So he'll be working to restore the benchmark functionality for this open-source Doom 3 BFG implementation, but equally as exciting as that he's planning to port the engine to the new Vulkan graphics API! Stay tuned for more updates.