I've decided to create an Atari Jaguar RGB cable using double shielded 75 ohm mini coax cable. Here is a picture of the progress so far. The cable will have separate cabling for the audio and RGB video. One stretch is to two RCAs for stereo audio, and the other is a premium 8 pin mini din plug for RGB input on a XRGB-mini!
Left and right audio soldered. Additional heat shrink tubing for all 4 connections to be shrunk!