We are regularly running into the need for easy production of html pages which allow the side-by-side display of English translation with the original Greek or Latin.
I think the target probably needs to be two or three column - probably two so that it will be usable on portrait size portable devices.
It also probably needs to be somehow divisible by "cells," in that the English translation is frequently longer than the Greek or Latin, and so to keep the passages of text together it's necessary to be able to have the end result look almost like a "spreadsheet" so that the English and original passages stay together. It's possible that links or tags could be used to jump from place to place, but ultimately side-by-side is probably the most usable.
Optimum would be the ability to easily change out the columns, so that for example the first column could be Latin, then the second switchable between Bailey, Munro, etc., with the switching function not causing you to lose your place in the text.
Since we're talking wish-list here, what we need is a system wherein the texts can be prepared and edited either locally or on the internet version, and then the result easily convertible to an html page for posting.
Currently one system I am using is Emacs org-mode, where I can prepare a text and then export the result to an html page like so. It's possible that emacs could do what we want but it has a steep learning curve.
I'd like to employ such as system to deploy side-by-side versions of Lucretius, rather than individually as we currently have it.
I made an early effort in the direction of multi-column pages here. This is somewhat usable, but it's not by any means optimum. The columns don't stay together and the system I used was not user friendly.
I know others would probably find suggestions useful, as Don (for one) is thinking about side-by side versions of his letter to Menoeceus.
I don't have any illusions that this will be easy to do, but if we start the thread now then maybe over time people will come across examples of other sites that are usable for such a project and we can explore how they are made.