First, different languages have different typographic convetions/traditions, so even though it may be usual to add a space before an ellipsis in English, it is most often wrong in Spanish, for instance.
In English ePubs, I tend to put a normal space before and after an ellipsis, when it is in the middle of a sentence (and by the way, I don't use … most of the time), and a at the end:
Code:
She would not sleep, she thought; she could last until tomorrow night. . . . The train wheels clicked in accented rhythm.
"But . . ." said Taggart, "but . . . but nobody's ever used it before!"
(in red, the actual ellipsis: . . .)
I don't think it's so wrong to break the line before an ellipsis in the middle of a sentence.