It appears that it is not after all a rumor and there is more to the iPad Mini. There have been images appearing over the Internet of the mold of the iPad Mini and what appears to be a next gen iPhone. Gotta Be Mobile has recently gotten hold of these pictures and they show the outline of the device as a whole.
This mold is what the third-party case manufacturers would be using to manufacture the cases for the iPad Mini. In the past, they have been the most authentic source for finding information about new or upcoming products. Last year, about the same time, there was a rumor about an iPhone 5 with a tapering design. Case manufacturers had been scrambling to verify this and it ultimately turned out to be a fake.
Coming back to the pictures of the iPad Mini mold, the dimensions of it are 213×143 mm. The new iPad however seems to be thinner than the current iPad 2, at only 9.39mm. The pictures also show a small dock connector, rumors of which had been floating around for a while.
The iPhone engineering sample photos also collected by Gotta Be Mobile seems to be molds and probably would be used in the same way to manufacture the final device. The appearance of the aluminum mold gives away a design that will have a large screen dominating the front of the device and will cover one edge to the other. Measurements would be very similar to the iPhone 4S, but slightly taller at 11.52cm. This, of course, could be because of the rumored larger display screen.
General appearance seems to suggest that both molds are authentic at least at the moment and could very well turn out to be full fledged devices soon. But having seen how rumors can go haywire, the best option would be to wait and watch.