Sadly, I don't think Lionel is interested in improving the ERR line, what you see is what we have I suspect. I have tons of ideas for new features, but I don't see them happening. Since I can't influence the static design of the ERR stuff, I stick band-aids wherever I can.
Marty, I'm going to offer some kits of parts for the serial data buffer, it's easy to build as I made it a mostly thru-hole design for that reason. I just have to wait until the boards show up from China and I'll have all the pieces. I've also posted the . I'd have to have hundreds assembled if I were going to have them manufactured, I don't see it ever being that much in demand. There's only five parts, and the only surface mount is the op-amp, I used one with reasonable lead spacing so it's pretty easy to solder. I posted all the details in the thread Improved R2LC/R4LC Serial Port Buffer.