I know that it isn't always practical or feasible to publish bilingual editions of translations, but when possible, I think publishers should do so. Such editions are good for language-learners, of course, and I remember a bilingual version of Carlos Fuentes' book Aura that I read when I was learning Spanish many years ago. But they are also great for people who are interested in translation, because then we can analyze the original and the translation in a convenient way.
I was thinking about this recently while reading a bilingual edition of Edward Lear's nonsense limericks, as translated to Spanish by a student of mine, Matías Godoy, and published by Destiempo Libros. Here, for example, is one page in the book:
Había una joven con una quijada
Igual a la punta de una larga espada;
Mandóla afilar, compróse un citar,
Y así tocó música con su quijada.
There was a Young Lady whose chin
Resembled the point of a pin;
So she had it made sharp and purchased a harp,
And played several tunes with her chin.
It's really nice to be able to see Lear's original with Godoy's translation. Poetry is particularly well-suited to bilingual editions due to its length, but I wonder if, as more people gain a deeper understanding of translation and what it involves, publishers might start to publish bilingual editions of prose as well.