I recently stumbled upon Sean Boisen's 2006 article
CSS for Interlinear Styling. Boisen suggested using the
display: inline-block; property instead of tables. I decided to give it a try and found out that it actually works for ePubs, too.
I created a short test epub that validates and displays correctly in ADE; the compiled Kindle KF8 version also displays correctly, but the regular .mobi version doesn't.