Well, I finally got around to modding my Master System for composite video output (RCA jacks). I have about a dozen Master System games that I have been meaning to play, but cannot stand the fuzzy noisy picture from the RF adapter. I didn't feel like shelling out $10 for a cable on eBay so I decided to spend $3.18 at RadioShack for some RCA phono jacks and add some RCA jacks to my Master System. This is my first time modding a console and my soldering skills are pretty poor, but I completed it in about 2 hours. I followed the directions from SMS Power and it came out great:
The quality difference between the standard RF adapter and a set of composite cables is night and day. The Master System does not actually output stereo sound, so the two audio jacks are outputting the same sound. I'm hoping to acquire a few cheap Master Systems to mod and sell on eBay if anyone is interested.