Triskeliongirl had a retrofit. I had a custom frame made with S&S couplers. I did ask my builder about retrofits, and he said he can't do it on many frames. It's a function of how the frame is butted. You can't put the coupler in a place where the frame internal diameter is changing. In a new build, the framemaker can control where the butts are. I think I understood him to say that older steel frames are more likely to be doable than more modern frames that have more serious butting. But maybe older frames are less worthwhile to convert for other reasons. So I think it's much easier to find a builder to custom build a new S&S frame than to find someone to retrofit couplers.
Oil is good, grease is better.
2007 Peter Mooney w/S&S couplers/Terry Butterfly
1993 Bridgestone MB-3/Avocet O2 Air 40W
1980 Columbus Frame with 1970 Campy parts
1954 Raleigh 3-speed/Brooks B72