I feel certain the Mini will go retina, and that when it does, it will do so exactly like all previous iOS devices: same physical size, double the pixel resolution. The only question is when. The iPhone went retina in the fourth generation; the full-size iPad in the third. Seems like too much to ask for the Mini to do so in its second.

John Gruber, on a AnandTech story 

I think it’s unlikely that the next iPad mini won’t go Retina. While the iPhone 4 introduced the technology, the 3rd gen iPad was a statement that it wouldn’t be restricted to the iPhone, being even extended to MacBooks later on.

When the iPad 2 came out non-Retina, it was ok because people were still hung up with the fact that they wanted a front-facing camera, and there was the fact that it also brought a gyro. Retina came to the iPad when the 3rd gen brought internal-only improvements.

Now the iPad mini already has all of that. It actually has the exact same hardware and features as the iPad 2. This is why if a second generation Mini (which will likely have the same hardware specs as the 3rd gen iPad) doesn’t go Retina, I’m not exactly sure of what they could do with. Unless they come out with an iPad mini S, with under-the-hood-only improvements, which wouldn’t be that exciting. Especially if this only happens a year from now.