I know and have exactly what you need

. I was going to get a RX8 which has a RGBS screen for the navigation so I bought a Extron RGB 109xi. It works perfect and I have tested it. I also have a couple straight through BNC cables. I could sell it all to you so let me me know if you are interested. I ended up buying a 2005 Mustang instead so I have no use for this equipment
The Extron RGB 109xi with ADSP is a dedicated computer-video interface with a 15-130 kHz scanning range, 300 MHz (-3dB) of RGB video bandwidth, and a 15-pin HD connector. It is compatible with VGA UXGA, Mac G3, and Mac G4 display signals, and will convert computer-generated, unbalanced audio to balanced, line level audio. Sync processing is achieved through Extron's exclusive Advanced Digital Sync Processing (ADSP) technology, ensuring compatibility with digital display devices such as DLP, LCD, D-ILA™/LCoS, plasma, etc.
Features
300 MHz (-3dB) RGB video bandwidth
Advanced Digital Sync Processing (ADSP)
Active PC audio to balanced audio interfacing
Three-position level/peaking switch
Horizontal centering control
Sync on green output (DIP switch-selectable)
Automatic sync stripping from red, green, and blue
Serration pulse removal (DIP switch-selectable)
Digital Display Sync Processing (DDSP™), DIP switch-selectable
ID bit termination on pins 4 and 11
Internal international
as you can see Extron is known for there video equipment

I also have two Extron RGBS video switchers for extra devices. Don't just convert the RGBS to Composite becuase you will lose alot of quality on the screen and it will look bad.
RGBS to VGA =