According to a new writeup on the site about the state of VC Earthbound, it's not coming. Like, ever. Legal issues, mostly with music licensing due to the preponderance of references to other works in the soundtrack, keep the game from being approved by Nintendo of America's legal department. And according to Starmen's source, the ESRB rating -- about which we rejoiced back in May -- was a mistake. A clerical error that nobody cared enough to correct. The ESRB went and rated the game, thinking that Nintendo wanted them to.
We're not entirely satisfied with this story. It handily explains why we haven't seen Earthbound in North America, but what about Japan? There didn't seem to be legal issues around the Mother 1&2 GBA release, and Earthbound is actually popular enough there to sell on the Virtual Console.