I don't see it happening. The main reason that kept Shigesato Itoi (who is the driving force behind the franchise) from TRYING to release the game in America was the fact that most of the songs used in the game are copyrighted, meaning that he'd have to change the songs a lot to prevent the game from causing lawsuits on Nintendo (which, even if they won, they'd still lose money because they'd have to hire laywers). Shigesato Itoi forsaw this (either that or Nintendo's legal department/whatever did) and decided that he didn't want to mess with the game's music (which I think was a wise thing to do).
Sure, every EarthBound fan around would go crazy and insta-buy it (including me even though I've got the handy dandy fan translation), but most people probably haven't even HEARD of the EarthBound games (even those who've played Smash Bros, although they're probably less likely to not know about the games than other people, and trust me, I know because I used to be one of those people) and probably wouldn't be too keen on investing money in a game they've 1) Never heard of and 2) Think is very quirky and strange (that actually put me off when I saw chuggaaconroy's EarthBound and MOTHER Let's Plays because it was so strange and boring to me, one of the biggest mistakes of my life).
Despite the fact that I say that Mother 3 probably won't come to America officially in the form of a 3DS release, I personally am praying to god that the planets align and bring Mother 3 to America officially.