On the Xbox 360 marketplace, the indie scene had any number of Minecraft knockoffs- Castleminer and Fortresscraft among them. You think the eShop will ever see anything like that? Would you buy it if it did?
I doubt it, but I wouldn't be surprised if we saw one. Minecraft was extremely successful on the PC and it makes sense to see all these knockoffs, but its craze and hype has dwindled in the past few months. If a knockoff did appear on the eShop, I wouldn't buy it. I already own Minecraft and there's a good chance that the 3DS knockoff would be inferior to it.