Mesh is the way to go. I ordered a ribbon from LA's DD 2 or 3 years ago and I bought some super fine mesh, got some tape, and went to town. I have glass lids, but there is a .5" space along the back for cords, and I just secured everything up. Nothing was getting out of there. Sadly, the eel did not survive shipping stress and was only with me a few days, so I never got to "test" it. I'm quite certain it would have worked though. The tank had absolutely no gaps.
As far as eating, I've heard that the "trick" is getting them started with dartfish. I knew someone who tried this on a few ribbons with consistent success over the years, and this person also knew a few other people who had much success with the same process.
I agree it's a fish not suited for everyone though, and most are best left alone. They definitely require extra care.